I use this book in my advanced college ESL class. My students didn't have to take the TOEFL, so I thought I would use the exercises for class. However, they are a little scattered and the answer key for each lesson in the back isn't necessarily easy to locate. I am able to gleen some extra exercises for class once in awhile, but I really wanted to use it as sort of a workbook for them to practice, but given that it isn't user friendly, I had to abandon that idea.