This book contains 10, 90-minute IQ tests, each containing 40 questions, but you won't be able to determine your IQ. The author states in the introduction, "The tests that follow have been newly compiled for this book and are not, therefore, standardised, so an actual IQ assessment cannot be given." Then what is the purpose of the book? Based on the number of questions answered correctly, you can determine if you are Exceptional (36-40 correct), Excellent (31-35 correct), Very good (25-30 correct), Good (19-24 correct) or Average (14-18 correct). If you are looking to determine your IQ, you will have to find a different book.