Wellington's Army, 1809-1814 (Sir Charles Oman, 1913) is a thorough overview of the personalities and organization of Wellington's Peninsular Army. I wish I'd read it years ago when I first started researching the military side of the Regency era. While it's not quite as encyclopedic, I think it makes a good companion to John Elting's book on Napoleon's army, Swords Around a Throne.
That said, I couldn't help noticing Oman's Edwardian point of view in spots. He pays more attention to the relatively few Methodist and Evangelical soldiers and officers than more recent accounts do, praising their pious and patriotic response to the atheism and destruction of tradition of the French Revolution. And he's shocked, SHOCKED, I tell you, and APPALLED that soldiers and even officers brought their WIVES along and generally collected female camp followers. He doesn't quite come out and say that war is no place for a woman and the ladies should've stayed back in England being Angels in the Home, but the implication is there. Which amused me, because one of the reasons I enjoy writing the Napoleonic Wars as opposed to many earlier and later conflicts is that there's so much scope for writing bad-ass female characters. Of course, I expect Sir Charles would've found me shockingly unwomanly--and I am a total tomboy, always have been except for my ill-fated attempts to be popular and girly as a teen.
However, I can't help thinking of something I read in CS Lewis years ago. Paraphrased, he said that it's a good idea to read works written before your own time, because each era has its biases in values and worldview. And you're not generally aware of your own time's skewed perspective, because you're soaking in it. So now I'm trying to figure out whether my view of of the Napoleonic era is more or less accurate than Oman's, and, on a related note, whether the present is more like the world of Oman's time or Wellington's. (My instinct is Wellington's, but I'm speaking from a West Coast, big city perspective. The world might look a little more Edwardian from the heartland.)