Shotguns are a subject I don't cover much, and I'll admit that's because of a prejudice on my part. I just don't find most of them to be particularly interesting...but then I had the chance to take a look at a collection that included a bunch of mechanically unusual and pretty fascinating shotguns. The owner is planning to drag me out to the range for some trap & skeet lessons, and I realized that I really should pay more attention to these guns. I wound up getting a couple (like my .410 SMLE, and a Spencer-Bannerman pump that will be in an upcoming video), and I also started looking for good reference books on them. I'm primarily going to be looking for martial guns, and the literature on those is pretty skimpy. Bruce Canfield and Joe Poyer both have books on US martial shotguns, Tim Mullin covered some types in his SMG/Shotgun/Machine Pistol evaluation, but the only reference I was able to find with an international scope was Thomas Swearengen's The World's Fighting Shotguns. Swearengen's book is dated (it was published in 1978), but it does a very good job of covering a wide variety of shotguns, from single shots to mag-fed aully automatic designs. It includes, for example, the 14ga Greener police guns (built on Martini-Henry actions), Spencer-Bannermans, Ithaca Auto & Burglars, High Standard bullpups, and the AA-12. Plus, of course, the more typical WWI and WWII trench shotguns, and a bunch of Philippine guerrilla kludges (I was a bit disappointed to see that the SMLE conversions are not included, though).