Here's an introduction to LaTeX2e,
The Not So Short Introduction to LaTeX2e(lshort). I got this document on http://learn.tsinghua.edu.cn:8080/2001315450/tex_frame.html and the following text are from the introduction.
TEX is a computer program created by Donald E. Knuth. It is aimed at typesetting text and mathematical formulae.
TEX is pronounced "Tech," with a "ch" as in the German word "Ach" or in the Scottish "Loch." In an ASCII environment, TEX becomes TeX.
LATEX is a macro package that enables authors to typeset and print their work at the highest typographical quality, using a predefined, professional layout. LATEX was originally written by Leslie Lamport. It uses the TEX formatter as its typesetting engine. These days LATEX is maintained by Frank Mittelbach.
LATEX is pronounced "Lay-tech" or "Lah-tech." If you refer to LATEX in an ASCII environment, you type LaTeX. LATEX 2ε is pronounced "Lay-tech two e" and typed LaTeX2e.