The book, The Piasecki H-21 Helicopter, represents the only comprehensive illustrated history of aircraft designer Frank N. Piasecki and his tandem-rotor H-21 advanced helicopter currently available.  The Piasecki H-21 was the first successful tandem-rotor cargo helicopter and it led the way to the development of both the CH-46 and CH-47 helicopters which remain in active service to this day.  "The Piasecki H-21 Helicopter" covers the early life of Frank N. Piasecki and his development of both the single-rotor PV-2 and later the XHRP-1 tandem-rotor helicopters.  Later improvements to the XHRP-1 led to the HRP-1 and HRP-2 both of which were flown by the United States Coast Guard and Marine Corps.  A subsequent request by the United States Air Force for a rescue helicopter that could function in the extreme cold of the Artic lead Frank Piasecki to develop the H-21 helicopter.  The United States Air Force evaluated the H-21, which lead to an order for the H-21 A "Workhorse" that went into service with both the United States Air Force and the Royal Canadian Air Force.  A further requirement issued by the United States Air Force lead to the development of the H-21 C, which was capable of carrying a fully equipped squad of soldiers into battle.  The H-21 C went on to be called the "Shawnee" and saw service in Burma, France, Germany, Japan and Sweden.  The H-21 was also purchased for use as a commuter aircraft by New York Airways.  H-21s were used early on in the Vietnam War and lead to the rapid expansion of helicopter use in this Southeast Asian country.  "The Piasecki H-21 Helicopter" book has an informative narrative along with plenty of illustrations and photographs.  It is highly recommended for both the helicopter enthusiast and modeler alike.  This book is 176 pages and is in new condition.  The authors are Robert J. Brandy and William J. Davies.  Edition published in 2007.