The information you can find in a library covers what a candidate needs to know to become a US Citizen including: how to apply, how to prepare for and pass the exam, and how to have a successful interview.
You can also find official USCIS questions and answers for lots of practice and a list of all of the English vocabulary words needed. Library branches offer books, DVDs, and toolkits on citizenship. These books come in English and other languages, such as Spanish, Arabic, Russian, and more. Many libraries also have a Citizenship Corner with information on how to prepare for the naturalization test.
Becoming a U. S. Citizen by 
The Civics and Citizenship Toolkit: A Collection of Educational Resources for Immigrants 2010 by 
How to Get a Green Card by 
Inmigraci�n: Las Nuevas Reglas. Gu�a Sobre Ciudadan�a e Inmigraci�n by 
Pass the U. S. Citizenship Exam by 
U. S. Immigration Made Easy by 