This book by Claudio Naranjo is one of the seminal books on the Enneagram. With chapters like "Envy and Depressive Masochistic Character (type 4)", "Gluttony, Fraudulence and Narcissistic Personality (type 7)" and "Pride and The Histrionic Personality (type 2)", this book doesn't pull any punches on the fixations of each type. As often seems to be the case with innovators in their field, Naranjo communicates a depth of insight on the types that goes beyond what is found in other works. Reading a chapter a second and third time reveals new understanding as there are layers upon layers of meaning in the content. It is as if the author, who knows a great deal more than they are communicating, is trying to pull out and distill a set of key insights or points for a broader audience to understand. Because of this attempt to dumb it down, you miss several nuances and points the first time you read it. It isn't light reading but I highly recommend this book.
I give this book 4.5 out of 5 stars. The only reason I don't give it 5 is my personal bias towards the practical. The book will appeal more to types that appreciate theoretical and conceptual content.