Hard to rate. Author is a bit wordy, but knows the subject well and is unbiased in his reporting. The book is informative, but the subject matter is very difficult. The questions brought up are interesting (what is truth, knowledge, justice, etc.). The answers given by various philosophers, at best, are obvious to any thinking person. And at worst, many "great" philosophers thoughts are trivial, silly or pure baloney. I kept expecting some enlightenment, but rarely found anything new that I found interesting. Many philosophers' points are so obtuse, that I had to re-read many paragraphs several times to understand what was being said. If you are looking for a light read that breezes through many great thoughts of the last centuries, then this book is a one star. If you are looking for serious details on a wide variety of topics, philosophers and their thinking (e.g. you are looking for a philosopher to study further), then it is a five star.