It definitely goes into more detail than Kaplan's book, although what they've got in there is essential to memorize, from what I remember. If you've got the time, you might want to bust out a biology text and study extra taxonomy from there. I say if you've got the time because studying from DAT-specific books is going to be higher-yield than just studying all the taxonomy from a biology book. I wish I'd had a little more time to focus on it, though, because it might have gotten me a few more biology points on the test.