I own the one by David Hucaby:
http://www.ciscopress.com/bookstore/product.asp?isbn=1587054574
Even though it was published five years ago it does a good job of covering the breadth of the product's capabilities.
If you are trying for certification, you may want to supplement your reading with one of the CCNP Security certification guides (VPN and Firewall), Those have both been updated in 2011 and 2012 respectively and thus cover the newer syntax in ASA 8.3+ code.
http://www.ciscopress.com/bookstore/product.asp?isbn=1587204479
http://www.ciscopress.com/bookstore/product.asp?isbn=0132748355