TeX[What is TeX?] is the typesetting language
He wrote a format of TeX called Plain TeX, but many people find
Plain TeX[Should I use Plain TeX or LaTeX?] complicated, so Leslie Lamport wrote a format of TeX called
LaTeX to make it a bit easier to use[How does LaTeX relate to
Plain TeX?]. You can think of LaTeX as a
go-between converting your instructions into TeX. This
document mostly uses the term LaTeX, even if the
matter is more general to TeX, to avoid complicating matters. Some
error messages you may see will be LaTeX messages, some will be
TeX messages. LaTeX error messages tend to be a bit easier to
understand than TeX messages. There are other formats of TeX,
such as ConTeXt[What is ConTeXt?], but this book
does not cover them.
This book is also available as A4 PDF or 12.8cm x 9.6cm PDF or paperback (ISBN 978-1-909440-00-5).