# Five basic classes

LaTeX2e provides style definitions for 5 basic classes of documents,
• article
• report
• book
• letter
• slides
Other classes are usually variations of the above; for example, the CU Thesis Class is a revision of the report class.

Not every LaTeX environment is defined in each of these classes. For example, you cannot use a figure or table environment in letter or slides classes. For example, you will get an error message if you use

\begin{figure}
\caption{Flow Chart of Operations}
.....
\end{figure}

in a letter or slides document. The available environments are summarized below.

article environment abstract description figure figure* quotation quote table table* thebibliography theindex titlepage verse