Many books have been written on the subject, and there are some introductory
texts available. M. Doob's `A Gentle Introduction to TeX, a Manual for Self-study' is
a fine article to start with. It can be obtained free of charge from many file servers
and is also available on the second CD-rom. It is even available in several languages!
See the directory \TEXCOURS for a complete list of available courses and introductions
to TeX on the CD-rom.
If you plan to use LaTeX you may want to read J. Warbrick's `Essential LaTeX', or G. Maltby's `An introduction to TeX and friends'. Both can be obtained from many file servers and the CD-rom. But after you have mastered the essentials of LaTeX you will soon feel the need for more documentation. This is provided by the L. Lamport's `LaTeX, A Document Preparation System', which is commercially available. The most complete book on LaTeX is `The LaTeX Companion' by M. Goossens, F. Mittelbach and A. Samarin. We will mention three other recommendable books on LaTeX: Kopka, H. and P.W. Daly: `A guide to LaTeX', Kopka's `LaTeX: Erweiterungsmöglichkeiten' in German, and R. Seroul and S. Levy's `A Beginner's Book of TeX'.
Advanced TeX and LaTeX users will often write their own macros and need much more insight. Their reference manual is `The TeXbook' by D. Knuth, the author of TeX. This is the most comprehensive work on TeX, but some consider it not very easy to read and understand for beginners. Another commendable book on TeX is V. Eijkhout's `TeX by Topic', which is not for the novice, but for users with basic understanding of TeX, who want to explore the full potential of TeX. S. von Bechtolsheim's multi-volume opus `TeX in Practice' is also a good choice.
In the bibliography you will find several more references to books about TeX.