Carteach0 has a review over on his blog about this book. After reading the review, and his recommendation, I ordered the book from Amazon. It got here a week or so ago, and I've been reading it in my "spare" time.
It's just fascinating.
Besides giving the history of machine guns, and semi-automatic rifles, it also has a lot of practical information, including the first explanation of "headspace", with drawings, that I actually understood.
And a lot of other interesting things, too, like "Experiments with Barrel Obstructions", "Gun Corrosion and Ammunition Developments", and more charts, tables, illustrations, and photographs than you can shake a stick or three at.
Truly and amazing work, and a definite "Must Have" if you're at all interested in the technical aspects of guns, ammo, and shooting.
I give it a "Five".