This book is a great overview of most of the characters in the DC universe. However, you wont find every single character in there, and alot of the entries are very brief. Even for characters with long histories and their own series. Its definately good value for what amazon are currently selling it for, and its a great place to start getting your head around the vast scale of the DC world, but using the word "difinitive" on the cover is a bit misleading. It could be twice the size and still not big enough to cover everything.