I have the hardcover version and also Waters book. I would not part with any of them. I read Waters a lot and I have used the data in Ackleys books, mostly the 44 mag and 45 colt. Several times I have referred Forum members to the Ackley chapters on pressure when questions arise as I believe His answers and data are informative and understandable. I think the soft cover versions would bring $25 to $30 each at a local gun show around here.