In legal writing you are expected to support your arguments with authority, and you must include appropriate citations for all the authority on which you are relying. The Bluebook: A Uniform System of Citation establishes the most commonly used format in legal writing.
The print version of the Bluebook is available to purchase at the student bookstore and from online retailers, such as Amazon.
The library has copies of the current (21st) edition on reserve and in the reference room, and these are available to you for up to two hours (for the reserve copies) and for use in the library (for the reference copies). A limited number of earlier editions of the Bluebook are available in the library stacks and may be checked out.
An alternate citation manual to the Bluebook -- The Indigo Book -- is freely available online. As explained in the Introduction to The Indigo Book (2d ed.), this book is "a free, Creative Commons-dedicated implementation of the uniform system of citation commonly used in United States legal documents. . . . The scope of The Indigo Book’s coverage is roughly equivalent to The Bluebook’s “Bluepages”—that is, The Indigo Book covers legal citation for U.S. legal materials, as well as books, periodicals, and Internet and other electronic resources."
Review the inside front cover -- The inside front cover of the Bluebook provides sample citation formats for the most commonly cited materials. It also identifies the citation rule associated with each format.
Use the back cover -- The back cover of the Bluebook offers a simplified table of contents, identifying the key rules and the page number where those rules can be found.
When you still cannot find the rule you need, try the index -- The index at the back of the book can be used to look up the type of source that you are trying to cite. However, it is spotty at best and is missing many types of sources.
Don't forget to abbreviate -- The Bluebook is picky about abbreviations. The abbreviation tables at the back of the Bluebook identify what abbreviations to use. The table of contents on the back cover of the Bluebook lists and provides the page number for each of the abbreviation tables.
You probably can overlook the blue pages -- When writing a paper, you will spend most of your time in the "white pages" and the tables at the back the Bluebook. The blue pages at the front of the book are intended more for practicing attorneys.
For more details, see the library's online Bluebooking workshop.
The below give good background and examples of the basic citation forms. For materials that fall outside these basic forms, often the best thing to do is search law reviews to see how other law review articles have cited them. Despite its name, the Bluebook is not especially uniform. It is missing citation forms for many kinds of materials and contains a lot of ambiguity. Generally, you will find several options to choose from, even if you are only searching the law reviews of the schools that author the Bluebook. For a Westlaw Custom Search page restricted to the journals of Bluebook authoring schools, email mcclelland at law.ucla.edu