What are the best study guides for ping the CLEP tests?

I will be taking some CLEP tests pretty soon and I am looking for the best study guides to learn the actual contents (With mock tests if possible) of the subjects to be tested for. I plan on buying the "CLEP Official Study Guide" and "Cracking The CLEP". If I understand correctly, these books teach more about the structure of the tests and not the material itself. Any help would be greatly appreciated. Thank You!