Essential LaTeX , by Jon Warbrick, gives all the essential information needed to use LaTeX . Only very basic features are covered... Available from CTAN (under info/latex-essential/); local mirror: tex, dvi, ps.gz.
Getting Started with LaTeX , by David R. Wilkins; local mirror: tex, dvi, pdf.
The Not So Short Introduction to LaTeX 2e is available from CTAN (under info/lshort); local mirror: tex, dvi, ps.gz.
A Gentle Introduction to TeX , by Michael Doob, (mdoob@ccu.umanitoba.ca) is an introduction to (plain) TeX for "rank beginners". This file is not difficult to find on the Web (search for "gentle.tex"); local mirror: tex, dvi, ps.gz.
An Introduction To TeX And Friends, by Gavin Maltby (gmaltby@unpcs1.cs.unp.ac.za, maltby@unpsun1.cc.unp.ac.za), is an introduction to the TeX world through LaTeX : covers text processing and mathematical typesetting. Around 80 pages. Intended for LaTeX beginners, especially those who want to typeset mathematics and proceed to AmSLaTeX .