CHRIS ROCK'S NEW DOCUMENTARY takes on an unlikely topic for the rangy comedian: African Americans and their hair. When his young daughter asks him why she doesn't have "good hair," Rock sets out to explore the massively profitable industry devoted to turning black hair into "good hair"—turning curly locks into straight, shiny ones by any means necessary.

There's a wealth of material here, from a black hair-care convention in Atlanta (featuring an outrageous styling competition that's more music video shoot than haircut) to temples in India where supplicants shave their heads in religious ceremonies—hair that's then processed and sold in the US to be used in weaves. This is probably the only documentary that will ever feature Raven-Symoné and Maya Angelou interviewed on the same subject (Al Sharpton has a fair amount to say as well).

Rock spends considerable time inside barbershops and salons, unearthing hair-care rituals and secrets. What he doesn't do, though, is give more than passing attention to the question of why so much money and effort is expended on black hair care. The explanation offered is textbook: The "beauty standard" is set by white people, therefore shiny, straight hair is more valued than curly hair. But even if you accept that premise, there's more to the story than that. One of the most interesting moments of Good Hair comes when Rock interviews a group of high school girls, all but one of whom have treated their hair into relaxed submission. One girl has a small Afro—and the other girls take turns explaining to her that even though her hair is "cute," it's unprofessional; that they'd never wear natural hair in the workplace. The girl with the Afro never says a word, just sits there, looking a little abashed. As the father of two daughters, it's this girl Rock should be talking to. Instead, he spends his time hassling women in salons, demanding to know how they pay for their weaves. It's an entertaining spectacle, but not an enlightening one.