1987, Aero / Tab Books (out of print)
This book is mostly a collection of first-hand stories from US Navy PBY veterans. Mr. Crocker has rolled these interviews into a "first-hand" history of the PBY during WWII. I've spent a lot of time with this book - it's loaded with history, told by the guys who made it.
Mel Crocker was an ARM3c (Aviation Radioman, third class) with VP-12, a PBY squadron serving in the Pacific during WWII.