The LaTeX Companion (Second Edition).
Frank Mittelbach, Michel Goossens, Johannes Braams, David Carlisle,
This is a good book to help you make the most out of LaTeX,
Useful LaTeX links
Comprehensive TeX Archive Network (CTAN)
TeX is the assembly language under LaTeX.
you can find free distributions of both TeX and LaTeX
for a variety of platforms.
Most Linux distributions that use
some kind of package or module installer
have a teTeX