TEXis one of the most used text formatting languages in
academia. Although very powerful, it is also quite complicated. Most
people who use it prefer to use the LATEXmacros at a higher level to
invoke TEXfunctions indirectly. LATEXitself is easier to learn,
and the very helpful interface latex-mode is available in Emacs
which allows the user to easily insert and edit LATEXcommands, to
execute latex (on either the file or just a particular region) in a
separate buffer without leaving the edited file, to invoke a DVI
previewer to immediately examine the corresponding results, and then
to print those results.
To use latex-mode, just load a file (with F11) that ends
with the standard extension .tex and Emacs will switch to
latex-mode for you. The file does not have to already exist.
However, if you prefer, you can press A-F2 to select
latex-mode directly to start editing in a new buffer or the
*scratch* buffer. If you are already in
latex-mode, then A-F2 will select plain-tex-mode,
if you wish to use TEXinstead of LATEX.