TeX is a tool for creating professional quality, typeset pages of any kind. It is particularly good, perhaps unsurpassed, at typesetting mathematics ; as a result, it is widely used in scientific writing. Some of its other features, like its ability to handle multiple languages in the same document and the fact that the content of a document (chapters, sections, equations, tables, figures, etc.) can be separated from its form (typeface, size, spacing, indentation, etc.) are making TeX more common outside of scientific and academic circles.
Designed by Donald Knuth in the late 1970s, more than a decade of refinement has gone into the program called “TeX” today. The resulting system produces publication-quality output while maintaining portability across an extremely wide range of platforms.A functioning TeX system is really a large collection of programs that interact in subtle ways to produce a document that, when formatted by TeX, prints the output you want. All the different interactions that take place ultimately result in less work for you, the writer, even though it may seem like more work at first. Heck, it may be more work at first, but in the long run, the savings are tremendous.
Remarkably, TeX is free. This fact, probably as much as any other, has contributed to the development of a complete “TeX system” by literally thousands of volunteers. TeX, the program, forms the core of this environment and is now supported by hundreds of tools.
Book Link:
http://makingtexwork.sourceforge.net/mtw/