Start with the web of course including Field Manuals.
Patrick Sweeney has some books out for Krause/Gun Digest/whatever that can likely be seen Barnes & Noble or Border's stores including 1911 Book 1 and 1911 Book 2 and now Big Book of the 1911 for look before you buy or order.
Dave Lauck has a book on the tactical 1911.
Kuhnhausen has his books 1 and 2. Layne Simpson has a very good and almost unique extensive book on the Custom 1911.