While necessarily brief and limited, this book makes for a nice place to start expanding your jazz interests. Coverage of old and new, mainstream and avant-garde, is remarkably well-balanced. Some key figures (Miles Davis, Louis Armstrong, Charlie Parker) get two entries each, but for the most part it's one per artist. I'm sure many people will kvetch about not covering their own obscure (or not-so-obscure favorite), but for every artist you think is missing, there are two or three remarkable others. The notes are brief but informative, covering important biographical details and sideman contributions, and i've only noticed a couple of minor errors (which is more than can be said for many jazz guides!)
A nice touch is the "We almost chose..." at the end of each entry, giving you two references for the price of one. All in all, this book is a good reference, if only because you can read it and learn new things without feeling like you're drowning in a sea of detail.