This book is worth every penny and more. I am studying for the ASE A6 Electrical examination. Electrical is my weakest auto technician area and this book is stuffed with questions and answered. I am sure I'll see a lot of them on the test, or at least almost the same as in the book. Most importantly I know what they are looking for in an answer. It also has a cross reference to the test study areas of the exam. I'm going to buy the who series ! I'm a tough rater, but this is 5 STARS !