The official CLEP study guide Princeton's Cracking the CLEP General Exams REA Test Prep for the General Exams COMEX Study Guide for CLEP Social Science and History www.instantcertonline.com Personally, my favorite is the COMEX study guide followed by Princeton's Cracking the CLEP. REA's is good also, but REA's sample tests are harder than the actual tests. I am also a fan of instacertonline. There is much information there on more than a single test and the monthly fee for accessing the study materials is reasonable.
this test covered a very large amount of information, none of which was very indepth. I used cracking the clep I dont know how helpful it was but i got a 66.