\gls*{tex}\faq{What is TeX?}{whatTeX}\ is the typesetting language
written by
\htmladdnormallink{Donald~Knuth}{http://www-cs-faculty.stanford.edu/~knuth/}.
He wrote a format of \TeX\ called Plain \TeX, but many people find
Plain \TeX\faq{Should I use Plain TeX or LaTeX?}{plainvltx}\
complicated, so Leslie~Lamport wrote a format of \TeX\ called
\LaTeX\ to make it a bit easier to use\faq{How does LaTeX relate to
Plain TeX?}{LaTeXandPlain}.  You can think of \LaTeX\ as a
go-between converting your instructions into \TeX.  This
\latexhtml{book}{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\faq{What is ConTeXt?}{context}, but this book
does not cover them.