I recently finished two books that purport to bust some of the myths that surround various aspects of US military history.
The first is "Dirty Little Secrets of Vietnam War" by James Dunnigan and Albert Nofi. In the '80's I knew Dunnigan from work with wargames (the Avalon Hill paper and cardboard variety, not the "Call of Duty" kind). From the title, you would expect top secret information to be divulged about nefarious operations and political wrangling. But while the book is good, it does not really contain "secrets" per se. It does have tons of stats and facts about the Vietnam war. Some of which dispel certain myths (such as the supposed "defeat" we suffered during the Tet Offensive in 1968) and backs up others (the gradual degradation in the morale and quality of the military during the war). If you are interested in learning the numbers behind some of the generalizations of the Vietnam War, I highly recommend this book. If you are looking for top secret blockbuster information, look somewhere else.
The second book is "Patriot Battles" by Michael Stephenson. This book goes over the armies on both sides of the American Revolution. The first half of the book has details on the men, weapons and equipment of the opposing ground forces. Although the jacket says it will dispel myths about the Continental Army, it really doesn't have any true revelations. Probably the most startling to the casual reader is the ineffectiveness of the American militias. The common view of the militias is that of brave men grabbing their musket from the mantle and heading off to fight the red coats at a minute's notice. In fact, the militia had a terrible record against the British in standard engagements. Only late in the war (such as at Cowpens and Guilford Courthouse) were they used effectively and then only as a screen for the line. The second half of the book has accounts of the major battles. My main gripe about the book is the author's occasional comparison between modern warfare (mainly Iraq) and the Revolutionary War. These comparison have a political tilt to them and come off as clumsy and out of place. The primary reason for the book seems to be to put the American side down. Very rarely does he give credit to the commanders and men in the Continential Army. The Amazon reviews have the same views, but a bit on the harsh side.