LaTeX/Package Reference

Here is a (not complete) list of useful packages that can be used for a wide range of different kind of documents. Each package has a short description next to it and, when available, there is a link to a section describing such package in detail. All of them (unless stated) should be included in your LaTeX distribution as package_name.sty. For more information, refer to the documentation of the single packages, as described in Installing Extra Packages.

The list is in alphabetical order.

amsmath	It contains the advanced math extensions for LaTeX. The complete documentation should be in your LaTeX distribution; the file is called amsdoc, and can be dvi or pdf. For more information, see the chapter about Mathematics.
amssymb	It adds new symbols in to be used in math mode.
amsthm	It introduces the proof environment and the \theoremstyle command. For more information see the Theorems section.
array	It extends the possibility of LaTeX to handle tables, fixing some bugs and adding new features. Using it, you can create very complicated and customized tables. For more information, see the Tables section.
babel	It provides the internationalization of LaTeX. It has to be loaded in any document, and you have to give as an option the main language you are going to use in the document. For more information see the Internationalization section.
bm	Allows use of bold greek letters in math mode using the \bm{...} command. This supersedes the amsbsy package.
boxedminipage	It introduces the boxedminipage environment, that works exactly like minipage but adds a frame around it.
caption	Allows customization of appearance and placement of captions for figures, tables, etc.
cancel	Provides commands for striking out mathematical expressions. The syntax is \cancel{x} or \cancelto{0}{x}
changepage	To easily change the margins of pages. The syntax is \changepage{textheight}{textwidth}%   {evensidemargin}{oddsidemargin}%   {columnsep}{topmargin}%   {headheight}{headsep}%   {footskip} All the arguments can be both positive and negative numbers; they will be added (keeping the sign) to the relative variable.
cite	Assists in citation management.
color	It adds support for colored text. For more information, see the relevant section.
easylist	Adds support for arbitrarily-deep nested lists (useful for outlines). See List Structures.
esint	Adds additional integral symbols, for integrals over squares, clockwise integrals over sets, etc.
eucal	Other mathematical symbols.
fancyhdr	To change header and footer of any page of the document. It is described in the Page Layout section.
fontenc	To choose the font encoding of the output text. You might need it if you are writing documents in a language other than English. Check in the Fonts section.
geometry	For easy management of document margins and the document page size. See Page Layout.
glossaries	For creation of glossaries and list of acronyms. For more information, see the relevant chapter.
graphicx	To manage external pictures.
hyperref	It gives LaTeX the possibility to manage links within the document or to any URL when you compile in PDF. For more information, see the relevant section.
indentfirst	Once loaded, the beginning of any chapter/section is indented by the usual paragraph indentation.
inputenc	To choose the encoding of the input text. You might need it if you are writing documents in a language other than English. Check in the Special Characters section.
latexsym	Other mathematical symbols.
listings	To insert programming code within the document. Many languages are supported and the output can be customized. For more information, see the Source Code Listings.
mathrsfs	Other mathematical symbols.
natbib	Gives additional citation options and styles.
pdfpages	This package simplifies the insertion of external multi-page PDF or PS documents.
rotating	It lets you rotate any kind of object. It is particularly useful for rotating tables. For more information, see the relevant section.
setspace	Lets you change line spacing, e.g. provides the \doublespacing command for making double spaced documents. For more information, see the relevant section.
showkeys	A useful package related to referencing. If you wish to reference an image or formula, you have to give it a name using \label{...} and then you can recall it using \ref{...}. When you compile the document these will be replaced only with numbers, and you can't know which label you had used unless you take a look at the source. If you have loaded the showkeys package, you will see the label just next or above the relevant number in the compiled version. An example of a reference to a section is . This way you can easily keep track of the labels you add or use, simply looking at the preview (both dvi or pdf). Just before the final version, remove it.
showidx	It prints out all index entries in the left margin of the text. This is quite useful for proofreading a document and verifying the index. For more information, see the Indexing section.
subfiles	The "root" and "child" document can be compiled at the same time without making changes to the "child" document. For more information, see the Modular Documents section.
subfig	It allows to define multiple floats (figures, tables) within one environment giving individual captions and labels in the form 1a, 1b.
syntonly	If you add the following code in your preamble: \usepackage{syntonly} \syntaxonly LaTeX skims through your document only checking for proper syntax and usage of the commands, but doesn’t produce any (DVI or PDF) output. As LaTeX runs faster in this mode you may save yourself valuable time. If you want to get the output, you can simply comment out the second line.
textcomp	Provides extra symbols, e.g. arrows like \textrightarrow, various currencies (\texteuro,...), things like \textcelsius and many others.
theorem	You can change the style of newly defined theorems. For more information see the Theorems section.
todonotes	Lets you insert notes of stuff to do with the syntax \todo{Add details.}.
siunitx	Helps you typeset of SI-units correctly. For example \SI{12}{\mega\hertz}. Automatically handles the correct spacing between the number and the unit. Note that even non-SI-units are set, like dB, rad, ...
ulem	It allows to underline text (either with straight or wavy line). Few examples of usage are added to the Fonts chapter.
url	It defines the \url{...} command. URLs often contain special character such as '_' and '&', in order to write them you should escape them inserting a backslash, but if you write them as an argument of \url{...}, you don't need to escape any special character and it will take care of proper formatting for you. If you are using hyperref, you don't need to load url because it already provides the \url{...} command.
verbatim	It improves the verbatim environment, fixing some bugs. Moreover, it provides the comment environment, that lets you add multiple-line comments or easily comment out big parts of the code.
wrapfig	To insert images surrounded by text. It was discussed in section Floats, Figures and Captions.
xypic	It is used to create trees, graphs, (commutative) diagrams, and similar things. See Xy-pic.