The author is Peter Guardino and the subtitle is A History of the Mexican-American War. This book brought the War to life for me as no other book has, most of all by considering issues of morale, organization, and how hard did the Mexicans really fight back (more than many sources claim). Here is one good “fact of the day”:

Between 1829 and 1860 around 14 percent of regular army soldiers deserted every year.

That’s for the American army, not the Mexicans. This one is good enough to make my best of the year list, so it will be on the addended version.