The Military & Police and it's later name, the Model 10. The .357 Magnum arrived in 1935, the M & P was already there. The .44 Magnum in 1955, the M & P was already there. The same with the Combat Magnum, the Model 13, the Chief's Special, and every other revolver. They made more M & P's and Model 10's than any other revolver that ever came out of the Smith factory. It served in WWII for how many countries and police forces around the world? The classic 4-inch version is of course the most commonly seen. It might not have been the most glamorous, but it was the workhorse of Smith & Wesson.