\documentclass{article,report,book or letter}

A LaTeX document starts with the command documentclass [option] {type}. The most common document-classes in LaTex are:

1. book
2. report
3. article
4. letter

All of them are similar, except letter. The main differences can be summerised as follows:

• An “article” does not provide “chapter”, whereas “book” and “report” do. Thus, the first structuring element of an “article” is section{name}.
• In a “book”, a header is automatically added to each page indicating the page number as well as the chapter name on even pages and the section name on odd pages
• A “book” is always 2-sided whereas in a “report” or “article” you have to specify it by using the “twoside” option. In addition, in a “book” and “report” the “titlepage” and “abstract” will take a whole page each, which is not the case for “article”. In an “article”, you can use the options “titlepage” and “abstract”.
• The “letter” provides a US-type letter format.

Available document structure commands:

Book: part{}, chapter{}, section{}, subsection{}, subsubsection{}, paragraph{}, subparagraph{}.

Report: part{}, chapter{}, section{}, subsection{}, subsubsection{}, paragraph{}, subparagraph{}.

Article: part{}, section{}, subsection{}, subsubsection{}, paragraph{}, subparagraph{}.

Letter: A letter does not know the same structuring commands as other formats, but more specific commands like signature{}, address{}, opening{} and closing{}.

Except part{}, all structuring commands build a hierarchy. They have a standard formating and numeration.

Other less common document-classes:

1. “proc” for a protocol (two columns by default and smaller borders on the left and right)
2. “slides” for a presentations
3. “minimal, a prototype for your own document type

You can always change the standard document types, by adapting the *.cls-file to your needs.