This question is asked often and there are a number of posts on it. Anway, I'll give you my input real quick. I would say there is not a single perfect book to study for the DAT from, so you probably need a couple of books. I would start with the Kaplan book as it is a good all around DAT book. However, it is a bit weak in Biology and its PAT sample questions are way to easy. I would get CLiff's AP bio or Schaum's Bio to review biology. Then get either Topscore DAT or DAT Achiever some good computer practice tests. If you want further help, try DAT Destroyer. Barron's DAT is good ONLY for help on the PAT section, but is helpful if you struggle with the PAT stuff.