• Essential LaTeX
• The Not So Short Introduction to LaTeX2e
• Essential Mathematical LaTeX2e
• Getting to Grips with LaTeX

The two best/most useful books on LaTeX are "LaTeX: A Document Preparation System" by Lamport and "The LaTeX Companion" by Goossens, Mittelbach, and Samarin. (That's gotta be one of the all-time great book titles...) My copies of these books will be on the shelf in room 123. There is also a 3-ring binder in room 123 that contains printouts of some of the files above, and others.