Not sure if "Basic Machines" by N.L. Davis was originally written for the military or for Coles original publication in 1977. In any case the military adapted it for their training purposes and made it available to the public. This is the military version. It is the same as the Coles version which I have in paper, with the exception of a couple of chapters on computer mechanisms, which were obviously obsolete for military purposes.
The book covers all of the basic fundamentals of machines and how they work. Block and tackles, wheels and axes, gears, internal combustion engines and much more. All of the principles are clearly illustrated with diagrams that make learning mechanical advantage easy. In this military version there is a large multiple choice quiz at the back to see how much you have retained.
If you have ever wondered how a depth charge works (haven't we all lol) This book has a clear explanation. To download go to my Books - Free Downloads page.