Like so many other homegrown American art forms, hip-hop dancing started off as a local thing. Guys (and some girls) in a certain neighborhood, maybe on a certain block, developed their own signature moves. Local heroes got the fans going at improvisational jams. It wasn’t the kind of dancing you did on a theatrical stage, or for a TV camera. For the Bronx’s original B-boys and B-girls, hip-hop was a way of life — a way of dressing and talking, a method of laying down beats and moving to them.

For at least 20 years, the crowd that gave the world B-boying, power moves, and Brooklyn uprocking has watched its dance forms get diluted and assimilated — first into a mainstream “breakdancing” craze, then, later, into amorphous “hip-hop” dance sequences in music videos and commercials. Enter Rennie Harris, 42, the Bessie-winning choreographer from Philadelphia who has made it his personal mission to document — and celebrate — hip-hop’s forgotten roots.

Mr. Harris’s latest show-cum-history lesson, “Rennie Harris’ New York Legends of Hip-Hop” (at the family-friendly New Victory), is a variation on the show he brought to the same theater two years ago. But while the formula is the same — a revue punctuated by snippets of video interviews with the legends — the focus this time is on New York dance styles and performers.

Mr. Harris doesn’t appear in the showcase, nor does he choreograph it; he serves as its “host,” choosing the acts (dancers, beatboxers, turntablists, a bucket drummer) and the bits of video history that connect them.

The show’s skimpy history, it must be said, won’t do you much good if you don’t already know a lot about hip-hop. The videos mostly consist of dancers reminiscing about the people who influenced them. There’s no one on hand to tell the uninitiated what they’re looking at, or why it’s special. If you don’t know popping from locking, West Coast funk from later East Coast forms, you won’t learn the distinctions by watching this show.

But if Mr. Harris’s show is an unguided tour of hip-hop, there’s plenty worth seeing. And Mr. Harris shows a rare knack for bringing hip-hop forms to a theatrical setting without destroying their spontaneity or their distinctive flavors.

What’s so refreshing about “New York Legends of Hip-Hop” is the way it brings to life hip-hop’s improvisational, jazz-like feeling. Each performer steers his instrument — drumsticks, turntable, or body — along a darting line, punctuated by small, witty surprises that get bigger as the act builds to its finish. The name of the game is rapport between the artist and the audience.

Take the quick-eyed Peter Rabbit, the show’s “bucket percussionist,” who starts his performance simply, by just whacking on some overturned buckets. Then he smacks the sticks together over his head to get the crowd clapping to the beat. Next he slips one drumstick between his teeth and drums with the other hand. Now he takes his shirt off while drumming one-handed. And now he flings the sticks over his buckets, leaps after them, and starts drumming on all available surfaces, before finally returning to his buckets and ending his number by flinging his sticks at the buckets and walking off. This guy knows how to build an act.

The same escalation principle runs through the rest of the beat-boxer and DJ solos, with the guys taking more and more risks. Part of the fun is seeing audience hands go up in the air to egg someone on.

The dancers also work the crowd, but there’s a limiting principle here: These purists are not about to give you splashy, MTV-style numbers full of power moves. At a “Legends” show, you get the integrity of the original dance forms.

You also get the entire package.When Mr. Harris opens up the show with a freestyle/house section, it’s complete with big hoop earrings, tube socks, and some seriously old-school moves — freezes, footwork, and jerking — performed with no-holds-barred energy by The Mop Tops (Jocelyn Rivera and Kim Holmes) and Caleaf “Looseleaf” Sellers.

Locking — a West Coast import with loose-jointed moves and eye-catching freezes — also has its own, almost vaudevillian number, featuring the quartet Face to Flave in black baggy knee-length pants and white Kangol berets. Later, popping gets its turn, as four dancers in huge, baggy suits jolt their bodies with abrupt muscle contractions.But again, this is purist stuff — no miming or Mr. Roboto routines.

To people who want to see a lot of headspins, a classicist like Mr. Harris may seem like a killjoy. The show’s B-boy/B-girl section (featuring original Rock Steady Crew member Pop Master Fabel, who serves more as icon than as a dancer) and its acrobatic section (starring Tic and Tac) are fun, but equally exciting routines can be seen in a subway station. And many of the finer points that Mr. Harris & Co. appreciate — such as the way a dancer drops from an upright position to the ground — may be lost on the untrained eye.

But that’s in keeping with the spirit of “New York Legends,” a show where the mainstream audience gets to see the kind of revue that insiders dream about. “New York Legends” is, in a sense, specialist fare, and its imperfections (like the long-winded videos) can make it feel like a local gathering. But that’s Mr. Harris’s point, after all. He’s determined to take us all back to the neighborhood to meet the men and women who started it all.

Until October 22 (209 W. 42nd St., between Broadway and Eighth Avenue, 646-223-3020).