On this page we gather book-related links: books published by TUG and others, discounts from various publishers, book reviews, and more. The lists are alphabetical by author. Listing on this page does not imply endorsement by TUG.
If you'd like your TeX-related book to be reviewed, please drop a line to firstname.lastname@example.org.
February 14, 2020. Review of The Art of Computer Programming, Volume 4, Fascicle 5 by Donald Knuth
October 12, 2019. Review of Hermann Zapf and the World He Designed: A Biography by Jerry Kelly
Books published by TUG - Books by Donald E. Knuth - Books about TeX and its applications - Books about typography and fonts - Other notable books - Affiliations and Discounts - Book reviews in TUGboat.
These books can be ordered through TUG, or from most online bookstores. They are also available electronically to TUG members.
|In June 2010, TUG published TeX's 25 Anniversary: A Commemorative Collection, a hardcover book of selected articles from TUGboat by Donald Knuth and other members of the original Stanford TeX project, with a foreword by Barbara Beeton and drawings by Duane Bibby.|
|In July 2009, TUG published TeX People: Interviews from the world of TeX, a book of more than fifty interviews from the TUG Interview Corner.|
Companion to the Papers of
Donald Knuth, by Donald Knuth, (Center for the Study of Language
and Information, Stanford, 2012. 441+xiii pp. Paperback,
$35.00, ISBN 978-1575866345. Hardcover, $70.00,
In this volume, Knuth explains and comments on the changes he has made to his work over the last twenty years in response to new technologies and the evolving understanding of key concepts in computer science. His commentary is supplemented by a full bibliography of his works and a number of interviews, which shed light on his professional life and publications, as well as provide interesting biographical details.
|Computers and Typesetting by Donald E. Knuth.
This Millennium Boxed Set—five elegantly printed books that describe their own method of creation—celebrates Knuth's monumental coupling of programming and typography. Originally published in 1986, each volume has changed so much in subsequent printings that nearly every page has been touched in some way. Improvements to the books have followed developments in digital printing technology; they also reflect corrections submitted over the years by thousands of volunteers.
Typography, by Donald Knuth, which collects most of his TeX-related
papers and reports (Center for the Study of Language
and Information, ISBN 978-1575860107, 685pp).
A discount for this book is available.
|The METAFONTbook by Donald E. Knuth.
Metafont is a computer language that allows you to produce professional quality typefaces using mathematical type design. The METAFONTbook, a users guide and reference manual, enables readers with only minimal computer science or word processing experience to master the basic as well as the more advanced areas of Metafont programming.
|The TeXbook by Donald E. Knuth. Available in hardcover or spiral bound.
Novice and expert users alike will gain from The TeXbook the level of information they seek. Knuth warns newcomers away from the more difficult areas, while he entices experienced users with new challenges. The novice need not learn much about TeX to prepare a simple manuscript with it. But for the preparation of more complex documents, The TeXbook contains all the detail required.
|The Art of
Computer Programming by Donald E. Knuth.
Boxed set, volumes 1-4A. This
multivolume work is widely recognized as the definitive description of
classical computer science. It was also Knuth's proximate cause for
creation of the TeX system.
|The Art of Computer Programming, volume 4A, part 1 by Donald E. Knuth.
In this long-awaited new volume, the old master turns his attention to some of his favorite topics in broadword computation and combinatorial generation (exhaustively listing fundamental combinatorial objects, such as permutations, partitions, and trees), as well as his more recent interests, such as binary decision diagrams.
|Algorithmic Barriers Falling: P=NP? by Donald E. Knuth and Edgar G. Daylight (Lonely Scholar, 2014, 116 pp.
Paperback, US$20.00. ISBN 978-94-9138-604-8).
By investigating Knuth's developing thoughts on the theoretical underpinnings of efficient computation, this book sheds light on Knuth's present-day conjecture that P = NP.
|The Art of Computer Programming, Volume 4, Fascicle 5 by Donald E. Knuth (Addison-Wesley, 2019, 382 pp.,
softcover, US$34.99, ISBN 978-0-13-467179-6).
This fascicle, brimming with lively examples, forms the first third of what will eventually become hardcover Volume 4B.
LaTeX and Friends, by Marc van Dongen (Springer, Feb. 29,
2012, x+330pp., 145 ill., 15 in color. Hardcover, $69.95
approx., ISBN 978-3-642-23815-4).
This book teaches all the ins and outs of LaTeX which are needed to write an article, report, thesis, or book. The book teaches by example, giving many worked out examples showing input and output side by side. The book presents the most recent techniques for presenting data plots, complex graphics, and computer presentations, but does not require previous knowledge. However, it is also a reference for the more seasoned user, with pointers to modern techniques and packages. Recurring themes in the book are consistent and effective presentation, planning and development, controlling style and content, and maintenance.
The Computer Science of TeX and LaTeX, by Victor Eijkhout (Lulu, 2012, 234 pp.
Paperback, US$17.05. ISBN 978-1-105-41591-3). PDF available (free) at http://eijkhout.net/texsci.
This book uses the TeX and LaTeX system to provide an introduction to a number of computer science topics.
This book is based on the lecture notes of a course taught at the University of Tennessee.
TeX by Topic. A TeXnician's Reference, by Victor Eijkhout (Lulu, 2011, 319 pp.
Paperback, US$16.61). PDF available (free) at http://eijkhout.net/texbytopic/texbytopic.html and CTAN.
TeX by Topic is a systematic
reference manual designed as a companion to tutorial guides on the
system. Packed with original, practical ideas, this book provides an
invaluable information source that will give the TeX user the essential
insight needed to solve TeX problems.
|The LaTeX Graphics Companion, 2nd Edition by Michel Goossens, Frank Mittelbach, Sebastian Rahtz, Denis Roegel, Herbert Voss.
The LaTeX typesetting system remains a popular choice for typesetting a wide variety of documents, from papers, journal articles, and presentations to books, especially those that include technical text or demand high-quality composition. This book is the most comprehensive guide to making illustrations in LaTeX documents, and it has been completely revised and expanded to include the latest developments in LaTeX graphics. The authors describe the most widely used packages, and provide hundreds of solutions to the most commonly encountered LaTeX illustration problems.
|The LaTeX Web Companion: Integrating TeX, HTML, and XML by Michel Goossens, Sebastian Rahtz, Eitan M. Gurari, Ross Moore, and Robert S. Sutor.
This book shows how you can publish LaTeX documents on the web. LaTeX was born of the scientist's need to prepare well-formatted information, particularly with pictures and mathematics included; the web was born of the scientist's need to communicate information electronically. Until now, it has been difficult to find solutions that address both needs. HTML and today's Web browsers deal inadequately with the nontextual components of scientific documents. This book, at last, describes tools and techniques for transforming LaTeX sources into web formats for electronic publication, and for transforming web sources into LaTeX documents for optimal printing.
More Math Into LaTeX, 5th edition, by George Grätzer (Springer. 609 pp. Paperback, US$67.99.
For over two decades, this comprehensive manual has been the standard introduction and complete reference for writing articles and books containing mathematical formulas.
Practical LaTeX, by George Grätzer (Paperback, 216 pp., Springer, 2014).
Practical LaTeX covers the material that is needed to compose everyday LaTeX documents. This accessible manual is friendly, easy to read, and is designed to be as portable as LaTeX itself. .
LaTeX, by David Griffiths and Desmond Higham (SIAM, ISBN
978-0-898713-83-1, 1997, 84pp).
A short example-based book covering
core LaTeX and a few packages.
|Guide to LaTeX, 4th Edition by Helmut Kopka and Patrick W. Daly.
This popular book shows you how to begin using LaTeX to create high-quality documents. The book also serves as a handy reference for all LaTeX users. In this completely revised edition, the authors cover the LaTeX2e standard and offer more details, examples, exercises, tips, and tricks. They go beyond the core installation to describe the key contributed packages that have become essential to LaTeX processing. As did the three best-selling editions that preceded it, Guide to LaTeX, Fourth Edition will prove indispensable to anyone wishing to gain the benefits of LaTeX.
|LaTeX Beginner's Guide by Stefan Kottwitz (Packt Publishing, Birmingham-Mumbai, 2011. 314 pp. Paperback, US$44.99).|
|LaTeX: A Document Preparation System, 2nd Edition by Leslie Lamport.
This authoritative user's guide and reference manual for the LaTeX computer typesetting system has been revised to document features now available in the new standard software release—LaTeX2e. The new edition features additional styles and functions, improved font handling, and enhanced graphics capabilities. Other parts of the book have been revised to reflect user comments and suggestions. Selected sections have been rewritten to explain challenging concepts or functions, and the descriptions of both MakeIndex and BibTeX have been updated.
|Tout ce que
vous avez toujours voulu savoir sur LaTeX sans jamais oser
le demander. Ou comment utiliser LaTeX quand on n’y
connaît goutte by Vincent Lozano (Framasoft; 2013,
Seconde édition. €15.00. ISBN 9791092674002).
All you always wanted to know about
LaTeX, but never dared to ask, in French.
|Introduction to LaTeX by Leo Liu (Publishing House
of Electronics Industry (China), July, 2013, 566
pp., Paperback, CNY ¥79, ISBN 978-7-121-20208-7).
Reviewed for TUGboat.
|Plain TeX with PostScript - Integrating Plain TeX with PostScript by William Maguire.
The book outlines a collection of the author's favourite TeX macros and PostScript procedures, which he has developed over the past three years. The book avoids the more esoteric aspects of plain TeX and covers macros totalling less than 1000 lines that can be used to produce a wide range of documents (including the book itself). Plain TeX offers the greatest flexibility in controlling font sizes, page layout and control of headers and footers without some of the constraints that are imposed by LaTeX packages.
Companion, 2nd Edition by Frank Mittelbach, Michel Goossens,
Johannes Braams, David Carlisle, and Chris Rowley.
The LaTeX Companion has long
been the essential resource for anyone using LaTeX to create
high-quality printed documents. This completely updated edition
brings you all the latest information about LaTeX and the vast range
of add-on packages now available—over 200 are covered. Full of
new tips and tricks for using LaTeX in both traditional and modern
typesetting, this book will also show you how to customize layout
features to your own needs—from phrases and paragraphs to
headings, lists, and pages.
LaTeX Companions, Third Revised Boxed Set: A Complete Guide and Reference
for Preparing, Illustrating, and Publishing Technical
by Frank Mittelbach, Michel Goossens, Sebastian Rahtz, Helmut Kopka,
This attractively priced boxed set
comprises four authoritative books on the LaTeX software system for
typesetting documents. Because LaTeX is especially good for
technical documents and is freely available for almost any computer
system, it has become a lingua franca of the scientific world.
Whether you are new to LaTeX or want to be sure that your LaTeX
library is current and complete, you will find a useful place for
this set on your reference shelf.
Let's Learn LaTeX, by S. Parthasarathy (http://www.freewebs.com/profpartha/teachlatex.htm, 24 pp., free ebook. Version 201408e)
This is a D-I-Y approach to learning LaTeX.
LaTeX for Complete Novices, by Nicola L. C. Talbot (Dickimaw Books, 2012, x+279 pp. Paperback,
GB£12.99. ISBN 978-1-909440-00-5).
This introductory book covers the very basics of LaTeX with exercises along the way to get you started.
Using LaTeX to Write a PhD Thesis, by Nicola L. C. Talbot (Dickimaw Books, 2012, x+279 pp. Paperback,
GB£12.99. ISBN 978-1-909440-00-5).
This is a follow-on from LaTeX for Complete Novices geared towards students who want to use LaTeX to write their PhD theses.
LaTeX for Administrative Work, by Nicola L. C. Talbot (Dickimaw Books, 2015, xiv+637 pp. Paperback,
US$33.99. ISBN 978-1-909440-07-4.
This book is aimed at people who want to use LaTeX for administrative work, such as writing correspondence, performing repetitive tasks or typesetting problem sheets or exam papers.
Apprendre à programmer
en TeX, by Christian Tellechea (Paperback, 580 pp., Lulu, 2014. Revision of 21/9/2014).
Progressive learning and educational programming in TeX language.
Tables with LaTeX, by Herbert Voß (UIT Cambridge, ISBN
978-1-906860-25-7, 2011, 240pp).
A practical book on typesetting
tables with LaTeX, covering many packages.
Mathematics with LaTeX, by Herbert Voß (UIT Cambridge, ISBN
978-1-906860-17-2, 2010, 304pp).
A practical book on typesetting mathematics with LaTeX, covering many packages.
LaTeX, by Herbert Voß (DANTE e.V., Lehmanns Media, 2012, 2012. 212 pp.
Paperback, €19.95. ISBN 9783865414960).
This books how show to create presentations with the two most important classes, powerdot and beamer. In addition to the basic functionality, examples illustrate how to realize a custom corporate design to create a custom document class or package.
PSTricks: Graphics and PostScript for
TeX and LaTeX, by Herbert Voß (UIT Cambridge, 2011. 928 pp.
Paperback, US$64.99. ISBN 9781906860134).
The book describes everything, from how to draw simple lines on curves, to creating three-dimensional images, trees, knots, charts, etc. The book contains hundreds of examples, with ready-to-run code, for hardcopy or PDF output.
LaTeX Quick Reference, by Herbert Voß (UIT Cambridge, 2011. vi+234 pp.
Paperback, US$29.95. ISBN 9781906860219).
This is a quick-reference book for LaTeX users.
Dynamic Documents with R and knitr, by Yihui Xie (Chapman & Hall/CRC Press, 2013, 190+xxvi pp.
Paperback, US$59.95. ISBN 978-1482203530).
Illustrates the extensibility of the popular knitr package, which was created by the author for doing reproducible research.
Histoire de l'écriture typographique–Le XXe siècle, Jacques André,
editorial direction. (Atelier Perrousseaux, Gap, France, 2016,
264pp.+364pp., ill.; also available as ebooks).
These are the last two volumes in the series The History of
Typographical Writing, comprised of seven volumes in all, from the
beginning of printing with Gutenberg through the 20th century. All are
in French. The individual volumes and the series as a whole are
available in various electronic and print formats; please see the
publisher's web site for current offerings.
Manual of Typography, by Giambattista Bodoni (Stephan Füssel, editor. Taschen, 2010.
1208 pp. Hardcover, US$69.99. ISBN 978-3-8365-0553-6).
The two-volume set—published posthumously in a limited edition of 250—features 142 sets of roman and italic typefaces, a wide selection of borders, ornaments, symbols, and flowers, as well as Greek, Hebrew, Russian, Arabic, Phoenician, Armenian, Coptic, and Tibetan alphabets.
|Palatino: The natural history of a typeface, by Robert Bringhurst (David R. Godine, Publisher; Boston, 2016,
296pp, ill. US$65.00. ISBN 978-1-56792-572-2).
Robert Bringhurst takes as his theme Palatino, probably the most widely known and used of all Zapf faces, and traces its development, with all its infinite permutations, and often invisible refinements through a long and fascinating history.
|Some Reflections on Reading and Writing, Culture and Nature, & Sorting Things Out, by Robert Bringhurst (RIT
Cary Graphic Arts Press; Rochester, 2016, Hand sewn
softcover, 12pp. US$20.00).
limited-edition pamphlet of Bringhurst's selected writings.
|What Is Reading For?, by Robert Bringhurst (RIT Cary
Graphic Arts Press; Rochester, 2011, Softcover, 40pp.
US$29.95. ISBN 978-1-933360-53-9).
This succinct and thoughtful essay is the text of a talk commissioned for a symposium entitled The Future of Reading which was held at RIT in June 2010. Written and designed by Robert Bringhurst, this limited edition is carefully crafted and letterpress printed.
|What Our Lettering Needs:
The Contribution of Hermann Zapf
to Calligraphy & Type Design at Hallmark Cards, by Rick Cusick (RIT Cary Graphic Arts Press,
Rochester. 2011. 136 pp. Paperback, US$24.95.
This book is a thorough account of Herman Zapf's contributions to the artistry and success of Hallmark Cards, an experience that is now fully blended into the company's rich heritage.
Just My Type: A book about fonts, by Simon Garfield (Gotham Books, 2011. 356 pp. Hardcover, US$27.50.
What does your favorite font say about you?
Shady Characters: Ampersands, Interrobangs and Other Typographical Curiosities, by Keith Houston (Penguin; 2015, xiv+340pp,
ill. Softcover. First published by Norton
in 2013. £9.99. ISBN 978-0-718-19388-1).
The secret life of punctuation, symbols, and other typographical marks
The Book: A Cover-to-Cover Exploration of the Most Powerful Object of Our Time, by Keith Houston (Norton; 2016, xviii+428pp, ill. Hardback.
First edition. $29-95. ISBN 978-0-393-24479-3).
A cover-to-cover exploration of the most powerful object of our time
|Design for Hackers. Reverse-Engineering Beauty by David Kadavy
Sons, 2011. 352 pp., Paperback, US39.99.
Learn the principles of beautiful design.
|The Noblest Roman: A
History of the Centaur Types of Bruce
Rogers by Jerry Kelly and Misha Beletsky (David R. Godine, Publisher, Boston. 2016. 128 pp.
Hardcover, US$45.00. ISBN 978-1-56792-582-1).
The story behind the type, the many permutations through which it went, the myths that accrued and surrounded it (many based on Rogers's somewhat eratic and chimerical memory) are all exposed in this fully documented account of the type's genesis and development.
|About more alphabets:
The types of Hermann Zapf by Jerry Kelly. Preface by Robert Bringhurst (The
Typophiles. 2011. 112 pp., 4.5′′× 7
This book, a companion volume to the Typophile Chapbook About Alphabets (1960, updated 1970), describes Zapf's post-1970 type designs and provides new research on many of the earlier types.
|The Art of the Book in the Twentieth Century by Jerry Kelly (RIT Cary Graphic Arts Press,
Rochester. 2011. 200 pp. Hardcover, US$39.95.
Through the selection of eleven master designers, Jerry Kelly illustrates a wide range of styles: from classically inspired design and historical revival, to novel and modern layouts.
|Hermann Zapf and the World He Designed: A Biography by Jerry Kelly (The Grolier Club, New York, 2019,
hardcover, 364 pp., US$48.00, ISBN 978-1605830827).
This is the first comprehensive biography of Hermann Zapf (1918-2015), whom Robert Bringhurst has called "the greatest type designer of our time, and very possibly the greatest type designer of all time.".
|W. A. Dwiggins: A Life in Design by Bruce Kennett (Letterform Archive, San Francisco, 496pp., US$95,
ISBN 978-0-9983180-0-4 (standard edition),
US$350, ISBN 978-0-9983180-1-1 (deluxe edition)).
Designer of books and types, calligrapher, illustrator, marionette engineer, and writer. W. A. Dwiggins was one of the most influential and innovative designers of the twentieth century, but what’s less known is the scope of his creativity, the fullness of his impressive body of work, and the inspiring attitudes with which he faced every challenge in life.
|Giambattista Bodoni: His
Life and His World by Valerie Lester (David R. Godine, Publisher; Boston, 2015, 288 pp., ill. US$40.00. ISBN 978-1567925289).
The first biography in English of the incomparable type designer, punch cutter, and printer, Giambattista Bodoni (1740-1813).
Examples of Calligraphy by Students of
Hermann Zapf, David Pankow, editor (RIT
Cary Graphic Arts Collection; Rochester, 2016, 60pp,
ill. Hardcover, paper over boards with vellum spine.
This book was conceived as a way to honor Hermann Zapf's legacy at RIT by offering a select group of accomplished former students an opportunity to share, through their art, what his Advanced Calligraphy classes meant to them.
A Specimen Portfolio of Wood Type in the Cary Collection (RIT Cary Graphic Arts Press,
Rochester. 2011. 305 pp. Spiral-bound, US$19.95. ISBN 978-1-933360-44-7).
This book showcases over 250 of our best wood type specimens, including many complete fonts and samples from unusual designs. All specimen reproductions were painstakingly printed from the original wood type blocks, some distressed with 100 years of use and abuse. The resulting compendium is a rich typographic resource sure to delight any designer, scholar, collector and student of graphic arts history.
|History of the Linotype by Frank Romano (RIT Press, 2014. 480 pp. Softcover, US$39.99.
From the Victorian era to the start of the twenty-first century, the Mergenthaler Linotype Company dominated the typesetting and printing industries. Unlike previous books which have ended with the invention of the Linotype, Frank Romano tells the rest of the story. This book details the products, the people, and the corporate activities that kept the company ahead of its competition in hot metal, phototypesetting, and pre-press technology. Over ten corporate entities eventually formed the U.S. manufacturer, which ended its corporate life as a division of a German press maker. What began in 1886 ended finally in May 2013, when the Linotype Library division of Monotype Imaging was closed down. After 127 years, the last resting place of the history of the Linotype Company is in this book.
The Calligraphy of Hermann & Gudrun Zapf, by Minako Sando & Akira Kobayashi (Japan
Letter Arts Forum, 2011, 64 pp. Paperback, US$29.95).
The exhibition was held in Tokyo in September, 2011. It was planned to be held in spring, which are the dates on the catalog, but it was postponed to September due to the earthquake and tsunami. The Japan Letter Arts Forum (J-LAF) and Akira Kobayashi, type director for Linotype GmBH, organized the exhibition.
Carol Twombly: Her Brief But Brilliant Career in Type Design, by Nancy Stock-Allen (Oak Knoll Press, Newcastle, 2016, 176 pp. Hardcover, US$49.95, ISBN 9781584563464).
This study is a fascinating inside look at digital type design, the rather mysterious career of one of its most important practitioners, and the history and culture of Adobe Type, with additional insight into other type designers of the digital era.
Never use Futura, by Douglas Thomas (Princeton
Architectural Press, 2017, paperback, 208pp., US$24.95,
By presenting Futura in both a historical and contemporary context, the book offers a cultural critique of its many uses.
Design Museum Fifty Typefaces That Changed The World, by John L. Walters (Alison Starling Publisher, 2013.
John L Waters explores 50 of the most influential typefaces and shows them in use on posters, perfume packaging, buildings and more.
|Alphabet Stories by Hermann Zapf (RIT Cary Graphic Arts Press,
Rochester. 2008. 150 pp. Hardcover, US$65.00.
Written as an anecdotal first-person account, the reader is treated to Zapf's personal recollections of technical breakthroughs. Zapf reveals milestones tracing his education in 1930s Germany, to his work on forefront of computer-aided typesetting in the 1970s, to the tour de force design of a complex calligraphic font — Zapfino in the late '90s. Vivid reproductions of Zapf's calligraphy, production proofs, typographic specimens, and photographs complete the portrait of one of the most prolific designers of our time.
Trees, maps, and theorems, by Jean-luc Doumont (Principiae, Kraainem, Belgium. 192pp. Hardcover, $96.00, ISBN 978-90-813677-07).
Based on hundreds of interactive training sessions,
Trees, maps, and theorems offers overall guidelines
and practical tips toward getting messages across
optimally in written documents, oral presentations,
and graphical displays.
Track Changes: A Literary History of Word Processing, by Matthew G. Kirschenbaum (The Belknap Press
of Harvard University Press, 2016, xvi+344 pp.
Hardcover, US$29.95. ISBN 978-0674417076).
Matthew Kirschenbaum examines how the interests and ideals of creative authorship came to coexist with the computer revolution.
Paper: Paging Through History, by Mark Kurlansky (W.W. Norton & Company, 2017, xx+389 pp. Paperback, US$16.95. ISBN 978-0-393-35370-9).
A definitive history of paper and the astonishing ways it has shaped today’s world.
The Imitation Game, by Jim Ottaviani & Leland Purvis (http://www.tor.com/stories/2014/06/the-imitation-game-jim-ottaviani-leland-purvis, 2014).
The Imitation Game by Feynman author Jim Ottaviani and Resistance illustrator Leland Purvis chronicles the life of Alan Turing in a full-size graphic novel.
A Truck Full of Money, by Tracy
House, 2016, xxiv+260 pp. Hardcover, US$28.00.
The story of Paul English, a kinetic and unconventional inventor and entrepreneur, who as a boy rebelled against authority.
Presenting data and information, by Edward Tufte.
One day seminar about data, information, presentatons and many other topics.
Unicode Standard: Version 5.0.
This new edition of Unicode's official reference manual has been substantially updated to document the latest revisions to the Unicode Standard, with hundreds of pages of new information. It includes major revisions to text, figures, tables, definitions, and conformance clauses, and provides clear and practical answers to common questions. For the first time, the book contains the Unicode Standard Annexes, which specify vital processes such as text normalization and identifier parsing.
Older reviews can be found on the TUGboat contents pages.
All discounts, except for Pearson's, are exclusive for TUG members in good standing. The codes for the discounts can be found in the TUG members area.
The procedure is to register at InformIT.com (Pearson's online store), and specify TEXUG for your “Discount Code”. Then any purchases at their store will receive the 30% discount.
The same offer applies to any book under any Pearson imprint: Prentice-Hall, New Riders, Peachpit and more. We've selected a few important TeX-related titles below.