# Document Style / Document Class

In LaTeX2, the very first command of a documents is \documentclass. This replaces the LaTeX2.09 command \documentstyle. Also, the \usepackage command has been added which is used in conjunction with \documentclass. However, LaTeX2 still understands the old \documentstyle command; if it is encountered, LaTex2 enters compatibility mode in which most LateX2.09 input files will still be processed properly (although the exact typesetting on the page, e.g. line- and page-breaks can differ in some cases).

Valid document classes include:

• article
• report
• letter
• book

They are selected with the following commands:
 Latex2.09 : \documentstyle[options]{class} Latex2 : \documentclass[options]{class} \usepackage[options]{package}

The options for the different classes that LaTeX2.09 and LaTeX2 have in common are:

• article:   11pt, 12pt, twoside, twocolumn, draft, fleqn, leqno, acm
• report:   11pt, 12pt, twoside, twocolumn, draft, fleqn, leqno, acm
• letter :    11pt, 12pt, fleqn, leqno, acm
• book :    11pt, 12pt, twoside, twocolumn, draft, fleqn, leqno

If you specify more than one option, they must be separated by a comma.

In LaTeX2, a number of new options where introduced. It is now allowed to explicitly specify the default text size: 10pt (in LaTeX2.09 the default was selected by omitting to specify a text size). Also, the paper size may be specified explicitly with options letterpaper (11×8.5 in), a4paper (29.7×21 cm), legalpaper (14×8.5 in), a5paper (21×14.8 cm), executivepaper (10.5×7.25 in), and b5paper (25×17.6 cm). The margins are adjusted automatically to have the text centered on the paper. The default orientation is to have the longest dimension be the vertical one, but this can be overridden by specifying option landscape. The text may be formatted in either single column (default) or two columns, corresponding to options onecolumn and twocolumn. The horizontal location of the text on the paper is normally the same on all pages, but may be made to differ on odd and even numbered pages using options oneside and twoside. In the case of the book class, chapters normally start on a right-hand, odd-numbered page, corresponding to option openright, but this may be overridden to use the earliest available page by specifying openany. The printing of a separate title page for the book and report classes may be suppressed by specifying the notitlepage option, while printing such a page can be forced for the article class with titlepage. Finally, the option final, which is the opposite of draft and the default, will not mark lines that are too wide.