Draco:
Mason's book sparked my interest in aviation and helicopters. It is also a superb and harrowing account of how the experience changed him. . .Years later he wrote another book about his life after leaving the army; you remember chicknhawk ends with him saying how he was done for drug smuggling? . .I've never been able to find the follow-up.
"The 13th Valley" by John M Del Vecchio . .ISBN 0-312-20081-1 is a fantastic book too, this time by one of the grunts that Bob Mason would have been transporting.