The denim shirt is the original blue collar. A longtime staple of cowboy and greaser wardrobes in the American film canon, nowadays the faded indigo icon is much more than a workshirt. It’s one of the many things Cool Hand Luke and Clint Eastwood have in common. True, it’s still at home in stable or garage, where the heavy twill weave is at its protective best. But as stylish as it can be, slide it under a suit and you’ve got options to armor yourself for the boardroom battles as well. These are the best denim shirts for fall.