Penrose presents an excellent challenge to the reader in this great book. Not only does it look thick before you start, but as you flip through it, you'll undoubtedly see symbols and equations you've never heard of. Unlike most pop-sci books today, "The Road to Reality" was written for a more serious lay reader with real mathematical applications and theories. If you're looking for a book that will teach you something about the mathematics behind the modern scientific discoveries, you should get this book. 5 stars.