What is LaTeX?

LaTeX is a TeXformat written in 1983--1985 by a computer scientist namedLeslie Lamport. LaTeX is based on the principle that authors shouldconcentrate on logical design rather than visual designwhen writing their documents. Thus instead of writing

\vertspace 1.5cm\begincenter\Large \bf2. Section Title\endcenter
LaTeX provides infrastructure that makes it possible for authors towrite
\section{Section Title}
and have not only the visual appearance but even the numbering bedone automatically.

LaTeX also has certain features designed to be used inconjunction with auxiliary programs makeindex andBibTeX that help automate the tasks of making indexes andbibliographies.

Around 1995, Lamport turned over the ongoing maintenance ofLaTeX to an international team of volunteers. There is a home pagefor LaTeX at

How do I use LaTeX to write a document?

Actually, you don't. You use some other program to write a LaTeXdocument, and then use LaTeX to "typeset" or "compile" thedocument. Programs such as Alpha, Emacs, BBEdit, WinEdt, vi, oreven NotePad can be used to write LaTeX documents. Some programs(e.g., Scientific Word) integrate the multi-step process intosomething closer to a typical word processor interface, but thefact that LaTeX software is mostly non-WYSIWYG is normally regardedas a virtue rather than a drawback. Among other things, it helps toclarify the distinction between visual appearances and essentialinformation that is important when it comes to reusing information.

How do I get LaTeX if I don't already have it?

If you want to get LaTeX up and running on a new computer, one ofthe best ways is with the TeX Live CD that youwill get as a benefit of membership in the TeX Users Group. Sign up tobecome a member and you will get a new one every year containingall the latest and greatest free TeX-related software. You caninstall software from the CD or even (in many cases) run itdirectly off the CD. This CD is not sold separately.

If you have a fast Internet connection, and want to download acopy of LaTeX in order to install it yourself, be advised that itnormally comes bundled as part of a much larger TeX distributionwith a whole slew of related programs, extension packages, andfonts, so it's a big download. There are a number of links given onour TeX Resources page, butyour best bets at the time of this writing (November 2001) are:

(Note: None ofthese links actually start a download, they just take you to arelevant page.)
The TeX Resources page also has links to a number of commercialdistributions of TeX that typically are easier to install and moretightly integrated into a given operating system (such as Textures forthe Macintosh, or Y&YTeX for Windows).

What is TeX?

LaTeX is based on another piece of software called TeX, writtencirca 1980 by Donald E. Knuth, a well-known computer scientist andmathematician at Stanford (with some important contributions from anumber of his students). Before you can use LaTeX, you need to havea working copy of TeX. However, you will normally find when you buyor otherwise obtain a copy of TeX that LaTeX comes with it (atleast the software, if not thebook).

Rather than attempting to be all things in a single package, TeXis designed with modularity in mind. Thus TeX itself provides onlyfundamental typesetting capabilities and does not incorporateediting, printing, or previewing capabilities; instead, the resultof running TeX is a graphics file in a format called "DVI" that isdesigned to make it as easy as possible for other programs to printor preview DVI files.

TeX formats

The fundamental typesetting capabilities of TeX operate on avery low level. They address the tasks of stringing characterstogether in words and paragraphs, automatically finding good pagebreaks, dealing properly with footnotes and other floating objects(such as figures and tables), and positioning symbols properly inmath formulas. But it is more natural for authors to work on asomewhat higher level: It is better to write

than to laboriously specify every aspect of the section title: fontsize, bold or italic, space above, indent or centered, etc.

Therefore TeX is designed to work with auxiliary packages calledTeX formats that add higher-level features at the authorlevel. LaTeX is a TeX format. Some other well-known ones are PlainTeX, AMS-TeX, eplain, texinfo, and Context.

What is Plain TeX?

Plain TeX is the generic example format that Knuth wrote to bedistributed with TeX. It is not really designed for seriouspublishing use---for example, it only provides one font size, youhave to define others yourself if you want to add them---but it wasquickly incorporated as a base element into other TeX formats suchas AMS-TeX and LaTeX.

American Mathematical Society