Books on TeX and its relations

While Knuth's book is the definitive reference for TeX, there are other books covering TeX:

The TeXbook
by Donald Knuth (Addison-Wesley, 1984, ISBN 0-201-13447-0, paperback ISBN 0-201-13448-9)
A Beginner's Book of TeX
by Raymond Seroul and Silvio Levy, (Springer Verlag, 1992, ISBN 0-387-97562-4)
TeX by Example: A Beginner's Guide
by Arvind Borde (Academic Press, 1992, ISBN 0-12-117650-9 - now out of print)
Introduction to TeX
by Norbert Schwarz (Addison-Wesley, 1989, ISBN 0-201-51141-X - now out of print)
A Plain TeX Primer
by Malcolm Clark (Oxford University Press, 1993, ISBNs 0-198-53724-7 (hardback) and 0-198-53784-0 (paperback))
A TeX Primer for Scientists
by Stanley Sawyer and Steven Krantz (CRC Press, 1994, ISBN 0-849-37159-7)
TeX by Topic
by Victor Eijkhout (Addison-Wesley, 1992, ISBN 0-201-56882-9 - now out of print, but see (La)TeX tutorials)
TeX for the Beginner
by Wynter Snow (Addison-Wesley, 1992, ISBN 0-201-54799-6)
TeX for the Impatient
by Paul W. Abrahams, Karl Berry and Kathryn A. Hargreaves (Addison-Wesley, 1990, ISBN 0-201-51375-7 - now out of print, but see (La)TeX tutorials)
TeX in Practice
by Stephan von Bechtolsheim (Springer Verlag, 1993, 4 volumes, ISBN 3-540-97296-X for the set, or Vol. 1: ISBN 0-387-97595-0, Vol. 2: ISBN 0-387-97596-9, Vol. 3: ISBN 0-387-97597-7, and Vol. 4: ISBN 0-387-97598-5)
TeX: Starting from Square One
by Michael Doob (Springer Verlag, 1993, ISBN 3-540-56441-1 - now out of print)
The Joy of TeX
by Michael D. Spivak (second edition, AMS, 1990, ISBN 0-821-82997-1)
The Advanced TeXbook
by David Salomon (Springer Verlag, 1995, ISBN 0-387-94556-3)
A collection of Knuth's publications about typography is also available:
Digital Typography
by Donald Knuth (CSLI and Cambridge University Press, 1999, ISBN 1-57586-011-2, paperback ISBN 1-57586-010-4).
and in late 2000, a "Millennium Boxed Set" of all 5 volumes of Knuth's "Computers and Typesetting" series (about TeX and Metafont) was published by Addison Wesley:
Computers & Typesetting, Volumes A-E Boxed Set
by Donald Knuth (Addison-Wesley, 2001, ISBN 0-201-73416-8).
For LaTeX, see:
LaTeX, a Document Preparation System
by Leslie Lamport (second edition, Addison Wesley, 1994, ISBN 0-201-52983-1)
Guide to LaTeX
Helmut Kopka and Patrick W. Daly (fourth edition, Addison-Wesley, 2004, ISBN 0-321-17385-6)
The LaTeX Companion
by Frank Mittelbach, Michel Goossens, Johannes Braams, David Carlisle and Chris Rowley (second edition, Addison-Wesley, 2004, ISBN 0-201-36299-6)
The LaTeX Graphics Companion:
Illustrating documents with TeX and PostScript by Michel Goossens, Sebastian Rahtz and Frank Mittelbach (Addison-Wesley, 1997, ISBN 0-201-85469-4)
The LaTeX Web Companion:
Integrating TeX, HTML and XML by Michel Goossens and Sebastian Rahtz (Addison-Wesley, 1999, ISBN 0-201-43311-7)
TeX Unbound:
LaTeX and TeX strategies for fonts, graphics, and more by Alan Hoenig (Oxford University Press, 1998, ISBN 0-19-509685-1 hardback, ISBN 0-19-509686-X paperback)
Math into LaTeX:
An Introduction to LaTeX and AMSLaTeX by George Grätzer (third edition Birkhäuser and Springer Verlag, 2000, ISBN 0-8176-4431-9, ISBN 3-7643-4131-9)

A list of errata for the first printing is available from: http://www.springer-ny.com/catalog/np/jan99np/0-387-98708-8.html

First Steps in LaTeX
by George Grätzer (Birkhäuser, 1999, ISBN 0-8176-4132-7)
LaTeX: Line by Line:
Tips and Techniques for Document Processing by Antoni Diller (second edition, John Wiley & Sons, 1999, ISBN 0-471-97918-X)
LaTeX for Linux:
A Vade Mecum by Bernice Sacks Lipkin (Springer-Verlag, 1999, ISBN 0-387-98708-8, second printing)
A sample of George Grätzer's "Math into LaTeX", in Adobe Acrobat format, and example files for the three LaTeX Companions, and for Grätzer's "First Steps in LaTeX", are all available on CTAN.

There's a nicely-presented list of of "recommended books" to be had on the web: http://www.macrotex.net/texbooks/

The list of Metafont books is rather short:

The Metafontbook
by Donald Knuth (Addison Wesley, 1986, ISBN 0-201-13445-4, ISBN 0-201-52983-1 paperback)
Alan Hoenig's 'TeX Unbound' includes some discussion and examples of using Metafont.

A book covering a wide range of topics (including installation and maintenance) is:

Making TeX Work
by Norman Walsh (O'Reilly and Associates, Inc, 1994, ISBN 1-56592-051-1)
The book is decidedly dated, and is now out of print, but a copy is available via sourceforge and on CTAN, and we list it under "tutorials".

This list only covers books in English: notices of new books, or warnings that books are now out of print are always welcome. However, this FAQ does not carry reviews of current published material.

Examples for First Steps in LaTeX
info/examples/FirstSteps (zip, browse)
Examples for LaTeX Companion
info/examples/tlc2 (zip, browse)
Examples for LaTeX Graphics Companion
info/examples/lgc (zip, browse)
Examples for LaTeX Web Companion
info/examples/lwc (zip, browse)
Sample of Math into LaTeX
info/mil/mil.pdf

This question on the Web: http://www.tex.ac.uk/cgi-bin/texfaq2html?label=books