Of the many youth subcultures that have sprung from pop music, few style cults have endured as long as mod, which involves an almost religious fealty to style as a way to transcend class distinctions. Now, after three decades, it is a perennial style with a well-defined set of mannerisms, chief among them an almost fetish-like attachment to mass-produced objects like Italian scooters and army-surplus parkas, and a devotion to certain types of music—the early Who, rhythm and blues, and ska. Over time, the original impetus for mod, a subversive sort of working class dandyism, has fallen away, and shorn of these implications—American mods are more apt to be suburban and middle class than urban and working class—it has become a quaint type of revivalism.

West Indian immigrants began to settle in London during the 1950s, an unsettling development for the traditionally xenophobic British, especially...