This is not the first book on the topic that I have read. I have always found it to be helpful to obtain information from a variaey of sources and authors, to avoid bias. The advantage,(and disadvantage,)of this book is that it gives you a brief synopsis of a variety of topics. It has a good bibliography in the back if you want to read more on the subject that interested you. In comparing the opinions of this author with other sources, I have found the information to be accurate, albeit limited in scope. I have given this book as a gift to several of my friends who are interested in exploring the topic. It serves as an excellent introductory volume. The book avoids getting into highly technical data, so it is an easy read for anyone, and with the relatively short chapters, each on an individual topic, you don't have to read it all in one sitting.