THE VERY WORD "hemline" can summon visions of midcentury women's fashion and the Byzantine bylaws that simply had to be followed whenever imperious French designers raised and lowered skirt lengths. Those crazy dames, right?

Guys, you're in the same game. For most of the past two decades, men's shorts have barely merited the name, dropping so far down the calf that Linnaeus would have stuck them in the pants family. Call them what you want—knickerbockers, breeches, clam...