This is a masterpiece on the four US helicopter pioneers -- Sikorsky, Bell (Arthur Young), Piasecki, and Stanley Hiller. Only faults to the book are (1) that it primarily focuses on the pioneers (hence the title), not the machines, and (2) he has nothing at all good to say about Hughes helicopters. In fact, it's pretty well damning. I think it should've been a little more objective. Also doesn't cover Charlie Kaman, who was also one of the early pioneers and still active today.

Whirlybirds is very well written account of the early history of the helicopter, and its pioneers. Filling a long needed gap in aviation history, this book tells how four men looked into the future of vertical flight, and turned it into a reality. This book is a must have. Jay Hendrickson