On February 27th, President Obama signed into law P.L. 111-141 (H.R. 3961), which extends key elements of the Patriot Act. Among these is the "library" provision (known as "Section 215") which allows the government to seek surveillance orders from the Foreign Intelligence Surveillance Court for tangible things, including medical and library records, that it states are related to a terrorism investigation.

Library records have historically been protected as private documents. In California, library documents are deemed confidential under Cal. Govt. Code § 6267 which reads that "[a]ll registration and circulation records of any library which is in whole or in part supported by public funds shall remain confidential". Additionally, the American Library Association, in its Code of Ethics (§ 3) states that "[l]ibrarians must protect each user's right to privacy with respect to information sought or received, and to materials consulted, borrowed or acquired."

ABA Government Affairs Office - March 2010 Washington Letter

Obama!  What are you thinking?!? -- Out of the Jungle (law librarian blog)

Congress extends library provision of Patriot Act to 2011 -- American Libraries