LaTeX is a document markup language and document preparation system for the TeX typesetting program. Within the typesetting system, its name is styled as .

LaTeX is most widely used by mathematicians, scientists, philosophers, engineers, scholars in academia and the commercial world, and other professionals. As a primary or intermediate format (e.g. translating DocBook and other XML-based formats to PDF), LaTeX is used because of the quality of typesetting achievable by TeX. The typesetting system offers programmable desktop publishing features and extensive facilities for automating most aspects of typesetting and desktop publishing, including numbering and cross-referencing, tables and figures, page layout and bibliographies.

LaTeX is intended to give a high-level language that accesses the power of TeX. LaTeX essentially comprises a collection of TeX macros and a program to process LaTeX documents. Because the TeX formatting commands are very low-level, it is typically much simpler for end-users to use LaTeX.

LaTeX was originally written in the early 1980s by Leslie Lamport at SRI International. It has become the dominant method for using TeX - few people write in plain TeX anymore. The present version is LaTeX2e (styled ).

Distributed under the terms of the LaTeX Project Public License (LPPL), LaTeX is free software.

The typesetting system

LaTeX can also be used to produce raster graphics.

LaTeX is based on the idea that authors should be able to centre on the meaning of what they are writing without being distracted by the visual presentation of the information. In preparing a LaTeX document, the author specifies the logical structure using familiar concepts such as chapter, section, table, figure, etc., and lets the LaTeX system worry about the presentation of these structures. It therefore encourages the separation of layout from content while still allowing manual typesetting adjustments where needed. This is similar to the mechanism by which many word processors allow styles to be defined globally for an entire document or the CSS mechanism used by HTML.

The example below shows the LaTeX input:\documentclass[12pt]{article}\title{\LaTeX}\date{}\begin{document} \maketitle \LaTeX{} is a document preparation system for the \TeX{} typesetting program. It offers programmable desktop publishing features and extensive facilities for automating most aspects of typesetting and desktop publishing, including numbering and cross-referencing, tables and figures, page layout, bibliographies, and much more. \LaTeX{} was originally written in 1984 by Leslie Lamport and has become the dominant method for using \TeX; few people write in plain \TeX{} anymore. The present version is \LaTeXe. \newline % This is a comment, it is not shown in the final output. % The following shows a little of the typesetting power of LaTeX \begin{eqnarray} E &=& mc
2 \\ m &=& \frac{m_0}{\sqrt{1-\frac{v
2}{c
2}}} \end{eqnarray}\end{document}

This input would produce the following LaTeX output:

LaTeX can be arbitrarily extended by using the underlying macro language to develop custom formats. Such macros are often collected into packages, which are available to address special formatting issues such as complicated mathematical content or graphics.

Pronouncing and writing "LaTeX"

LaTeX is typically pronounced /ˈleɪtɛk/ or /ˈlɑːtɛk/ in English (that is, not with the /ks/ pronunciation English speakers normally associate with X, but with a /k/). The last character in the name comes from a capital Χ (chi), as the name of TeX derives from the Greek τέχνη (skill, art, technique); for this reason, TeX's creator Donald Knuth promotes a /tɛx/ pronunciation (that is, with a voiceless velar fricative as in Modern Greek, or the last sound of the Scottish word "loch" or the German word "Bach", similar to the Spanish "j" or Arabic "خ" sounds). Lamport, on the other hand, has said he does not favor or discourage any pronunciation for LaTeX.

The name is conventionally printed with the special typographical logo shown on this page. In media where the logo can't be precisely reproduced in running text, the word is typically given the unique capitalization LaTeX to avoid perplexity with the word “latex”.

Licensing

LaTeX is typically distributed along with plain TeX. It is distributed under a free software license, the LaTeX Project Public License (LPPL). The LPPL is not compatible with the GNU General Public License, as it requires that modified files must be clearly differentiable from their originals (typically by changing the filename); this was done to ensure that files that depend on other files will produce the expected behavior and avoid dependency hell. The LPPL is DFSG compliant as of version 1.3. As free/open source software, LaTeX is available on most operating systems including Linux, Unix (including the BSDs), Windows, Mac OS X and AmigaOS. The first DVI previewers capable of on-screen previewing and modification of LaTeX documents were Amigas.

As a macro package, LaTeX provides a set of macros for TeX to interpret. There are many other macro packages for TeX, including Plain TeX, GNU Texinfo, AMSTeX, and ConTeXt.

When TeX "compiles" a document, the processing loop (from the user's point of view) goes like this: Macros > TeX > Driver > Output. Different implementations of each of these steps is typically available in TeX distributions. Traditional TeX will output a DVI file, which is typically converted to a PostScript file. More recently, Hàn Thế Thành and others have written a new implementation of TeX called pdfTeX, that also outputs to PDF and takes advantages of features available in that format. The XeTeX engine developed by Jonathan Kew merges modern font technologies with TeX.

The default font for LaTeX is Knuth's Computer Modern, which gives default documents created with LaTeX the same distinctive look and feel as those created with plain TeX.

Versions

LaTeX2e is the current version of LaTeX. As of 2008, a future version called LaTeX3 is in development. Planned features include improved syntax, hyperlink support, a new user interface, access to arbitrary fonts, and new documentation.

There are numerous commercial implementations of the entire TeX system. System vendors may add extra features like extra typefaces and telephone support. LyX is a free visual document processor that uses LaTeX for a back-end. TeXmacs is a free, WYSIWYG editor with similar functionalities as LaTeX but a different typesetting engine.

A number of TeX distributions are available, including TeX Live (multiplatform), teTeX (deprecated, Unix), fpTeX (deprecated), MiKTeX (Windows), MacTeX, gwTeX (Mac OS X), OzTeX (Mac OS Classic), AmigaTeX (no longer available) and PasTeX (AmigaOS) available on the Aminet repository.

Notes