ACT Prep is a book used to prepare students taking the ACT. It covers the concepts you need to know for the test, honing in on individual concepts in each subject (ELA, Math, Reading, and Science). There is also a review on the Writing section for anyone who plans to take it. There are also plenty of test strategies covered and things you need to do on test day. There are many high-quality practice tests that have very detailed solutions so you can understand what you did wrong and what mistakes not to make next time. There are more practice tests online on the Princeton Review website after you enter the code given in the book. They provide information on the new online testing option as well. The practice tests in this book are much harder than the actual ACT. This can be helpful because with good preparation that the test can seem less stressful; however, it also makes it so the practice tests (especially the Science section) are quite different from the actual ACT. There are two practice tests online that must be printed if you plan to practice similarly to the actual ACT. Because of all this, I give this book a 4 out of 5.