LaTeX is most widely used by mathematicians, scientists, engineers, philosophers, 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 high 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 provide 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 usually 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 current version is LaTeX2e (styled ).
The term LaTeX refers only to the language in which documents are written, not to the text editor itself. In order to create a document in LaTeX, a .tex file must be created using some form of text editor. While many text editors work, many people prefer to use one of several editors designed specifically for working with LaTeX.
The example below shows the LaTeX input and corresponding 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. Indeed, in the example above the
eqnarray environment is deprecated by the
amsmath package, which provides the typographically better
align environment for the same purpose.
LaTeX is usually 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 German word "Bach", similar to the Spanish "j" sound). Lamport, on the other hand, has said he does not favor or discourage any pronunciation for LaTeX.
The name is traditionally printed with the special typographical logo shown on this page. In media where the logo cannot be precisely reproduced in running text, the word is typically given the unique capitalization LaTeX to avoid confusion with the word "latex". The TeX, LaTeX and XeTeX logos can be rendered via pure CSS and XHTML for use in graphical web browsers following the specifications of the internal LaTeX macro.
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 (usually 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, RISC OS and AmigaOS. The first DVI previewers capable of on-screen previewing and modification of LaTeX documents were Amigas.
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 are typically available in TeX distributions. Traditional TeX will output a DVI file, which is usually converted to a PostScript file. More recently, Hàn Thế Thành and others have written a new implementation of TeX called pdfTeX, which also outputs to PDF and takes advantages of features available in that format. The XeTeX engine developed by Jonathan Kew merges modern font technologies and Unicode with TeX.
The default font for LaTeX is Knuth's Computer Modern, which gives default documents created with LaTeX the same distinctive look as those created with plain TeX.
LaTeX2e is the current version of LaTeX. , a future version called LaTeX3 is in development and it has been since the beginning of 1990s. 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 additional 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. Other WYSIWYG editors that produce LaTeX include Scientific Word on MS Windows.
A number of TeX distributions are available, including TeX Live (multiplatform), teTeX (deprecated in favour of TeX Live, 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.