Geoffrey Wawro is the General Olinto Mark Barsanti Professor of Military History at the University of North Texas, and Director of the UNT Military History Center. His primary area of emphasis is modern and contemporary military history, from the French Revolution to the present.
Really comprehensive, really factual--probably the best history book I have (and believe me, I have A LOT). It is quite current as well, going all the way up to 2008, so it has information on some more recent issues. Hopefully this will help me get an A+ on the Russian Revolution!
The only problem is that I got it in a state of disrepair--the front cover has literally fallen off and a lot of the pages have fallen out! Oh well, it's still readable haha.