i have a few books on MA, specific to forms like dr. yang, jwing-ming : comprehensive application of shaolin chin na (as well as the analysis book) and a several daitoryu akijujutso books, but, the one i would recommend is
cheng hsin: the principles of effortless power, by peter ralston.
its a descriptoin of some of the base level techniques of power, described in a realistic linguistic form. when such terms as "connection to mother earth" are used, it can get pretty hard to understand what exactly the old forms are talking about. in that book, one of the meanings to that, is the alignment of the bone structure to allow for the transfer of force from the fist (or whatever body part) though the skeleton, into the ground. like when you push a car up hill, do you do so on the ball of your foot, or on your heels? heels, because your bone structure is sinking down into proper alignment for taking force, and taking as much weight as it can. same principles should be applied to getting real powerful force into your punches and such...
that probably wasnt the best description of what this book is, its very deep, and has a lot to offer page by page. my brother response being "i'm going through the chen hsin again... i honestly beleive that im going to reread it every 5 years, and get something new out of it... some deeper understanding"