CLIO is the online catalog to Columbia University Libraries (including Barnard), but excluding Teacher's College and the Law Library who maintain their own catalogs. CLIO contains over 7 million records for books, online resources, journals & newspapers, conference proceedings, sound recordings & scores, videos, archival collections & oral history transcripts, online databases, maps & images, and more!
Text or email the call number to yourself.
Borrow Direct or Interlibrary Loan are great options for requesting a book that isn't currently available at the Columbia libraries.
Worldcat searches libraries worldwide. Using Worldcat, you can quickly find out if an item might be available at the NYPL, or another academic library (if the latter, try Borrow Direct or ILL to request from off campus).
The NYPL catalog searches the circulating and non-circulating research collections at the New York Public Library. The Archives and Manuscripts search page allows for exploration of special collections.