At the outset of his very smart, very funny new book, "Uniforms," Paul Fussell asserts that "everyone must wear a uniform, but everyone must deny wearing one, lest one's invaluable personality and unique identity be compromised. If you refuse to dress like others, you will be ridiculed, and no one wants to appear in public dressed like a fool or an oddball." An astute historian and social critic ("The Great War and Modern Memory," "Class"), Fussell is talking mostly about Americans, but when he says "everyone" he means it, from the banker in the dark suit to the professor in the blazer and khakis. If you are part of a group, you dress like the group. But "Uniforms" is most interesting at its most obvious, when Fussell talks about the real uniforms on cops or nurses or soldiers, and explains why we think about these people the way we do based on what they wear. The Postal Service, he points out, is so persnickety about its reputation for trustworthiness that postal workers who might stop off for a beer after work are not allowed to do so while in uniform. You can file a lot of what Fussell says under "interesting trivia": Queen Victoria popularized the white wedding dress (before that, wedding gowns came in any color) and the habit of dressing small boys in sailor suits. But the heart of his thesis--that the symbolism of uniforms does work--is a fact too often underestimated. The next time you're in an airport and think the pilots look silly in their faux-military get-ups, look at it Fussell's way: would you get on a plane if they were wearing cutoffs?