My first book was not an epoch shattering history but a fitness handbook based on the training regime I followed when training to do regular SAS selection back in the late 1980s (I got blown out for being too short-sighted), expanded to include some general fitness programs, some dietary and kit advice and some pointers about fitness training in the great outdoors. It’s fairly simple stuff but it does work: a good number of people have used the book to train for SAS selection and have got through, but many more have just followed the general fitness advice presented in it.
Adrian Weale 
a very good book. thoroughly enjoyed reading it. found it a very usefull guide on how to get to the level of fitness required for the sas. plan on following albeit slightly modified when i hopefull start training for the london marathon.
This book is the best book I have ever read. As a “Desk Driver” I followed the shopping list, menus and diet, to the letter. I followed the training program, also, to the letter.
I had to shed 2 stone to meet British Military entry requirements.
Within 7 weeks, I had lost 2 and a half stones (35 lbs) and could complete the 1.5 mile BFT in under 9 minutes and 20 seconds.
Best book for preparation EVER…!