This study guide is a valuable tool for a subject/textbook that is very in-depth and overwhelming with information. However, the Practice Exams in the workbook were extremely disappointing. The answer key did not give answers that were even choices for the corresponding questions (i.e., the answer for #1 (for example) would be "J" but the listed answer choices for #1 were only A, B, C, or D) -- this was repeatedly an issue and did not happen on just one or two questions. It was frustrating to study that hard & put full effort into the questions, then to find out you couldn't even rate how you scored. The outlines provided for the chapters in the study guide were helpful, though, so there is some value to the study guide, but you can also use the FREE online resources that are available on evolve.com (see the textbook for more info) -- that website has sample tests, etc that are really helpful and FREE!! (By the way, I have notified the publisher of their errors in the workbook & have still received absolutely no response. Disappointing.)