I first came upon Osprey books while I was in New Orleans for a medical convention. Lots of titles caught my interest, and I read them quickly. They are short, in the whole, and chock full of information, as well as lots of illustrations. There are several different series, more seem to crop up all the time.
I don't follow them all. Specifically, I don't pick up Aviation Elite Units, Battle Orders, Essential Histories, Essential History Specials, Force on Force, General Aviation, General Military, Graphic History, Modelling Manuals, Modelling Masterclass, Osprey Modelling. For the most part, these don't interest me. There's also some wargaming rules sets; I haven't read or purchased any, but I'm slowly considering it.
Now, there's still a number of series that I *do* follow. I don't buy every book in each of these series, but I read a lot of them.
I started with Men-at-Arms. These deal with soldiers in various eras and wars throughout history. There's nearly five hundred titles now, though not all are in print.
Next was Campaign. This series dealt with famous battles or series of battles and covers their commanders, background, forces, gear and sequelae. They tend to be the longest of these books, as they are more complicated. There's about 250 of these.
Then I started to follow Elite. These books are about forces throughout history that were considered the best of their eras, or their national forces. There's nearly two hundred of these. Recently, as they've covered most of the world's best forces, they're using these books to deal with tactical guides, especially from WWII.
At one point, while we still lived in Chicago, I picked up a couple of books of the Combat Aircraft series from a used book store. It's not one that I really like all that much. There's less than a hundred books in this series.
Then there's Warrior. I don't really know what makes this series different from Men-at-Arms, but it deals with the arms, tactics and era of various military traditions. There's over 160 of these.
Next is Vanguard, which disappeared before I started collecting these books. It dealt with military equipment. I don't know how many there were, but it faded out. Thereafter, they opened up New Vanguard, which still deals with military hardware which mostly don't fly (zeppelins and shuttles excepted). Since the restart, there are nearly two hundred books.
Newer still is Fortress. This series deals with castles, bases, fortifications from all of history. There's over a hundred of these, and I do appreciate the graphics; they do give a good feel of what the defenders' point-of-view would be.
More recently is Command. It deals with the most famous of generals. So far there's about twenty-five of these.
And then there's Raid. They depict the tales of the most famous battles; short, sharp and important. There's been thirty so far.
I also have looked at a few of the Weapon series. They detail a variety of items of military use. So far there's less than twenty.
I've found a couple of ebooks of Duel and Aircraft of the Aces. I haven't read any of them. Duel deals with a comparison of two military systems in conflict, such as T34 tanks versus Panther tanks. The other series deals with military airplanes and the ace pilots who flew them.
These books cover famous and obscure forces, and they fill a gap in history very nicely. I like them, generally, though some are better than others. So, if you see me posting about the many more that I'm likely to read, you'll have some idea why I've chosen them.