"People may not realize it, but they are hearing and seeing a revolution in black music and dancing," says Robert Farris Thompson, a professor of arts history at Yale University and one of this country's authorities on African and Afro-American art and culture. He is referring specifically to the "hiphop" movement, which encompasses breakdancing, rap music and graffiti art, a movement that has grabbed America's attention via the airwaves, the movies, in theaters and, most significantly, city streets.

In his search for breakdancing's origins, the effusive, mustachioed Thompson has covered a lot of territory, both historical and geographic. Wednesday night at the Museum of Natural History's Baird Auditorium, Thompson will present his findings in a lecture entitled, "Before Breakdancing: Art and Sport in the Black Atlantic World." Employing slides, a film exploring Afro-Brazilian martial arts, and his own combination of verbal wit and outrageous physical gesture, Thompson will trace breakdancing and its accompanying forms from the South Bronx to South America, and eventually back to Africa. Thompson's goal is to make his subject matter as exciting and accessible as possible. "I try to give people the flesh and blood black heroes of art and music, keeping the message at a down-to-earth level," he explains. "I don't want their grandeur obscured by theoretical musings."