By Michael Endelman
April 16, 2004 at 04:00 AM EDT

WHAT IS IT? Proof that beats know no boundaries, reggaeton is a Spanish-language, pan-American fusion of Stateside hip-hop rhymes, Puerto Rican salsa flourishes, and Jamaican dancehall rhythms.

WHERE IT COMES FROM In the early ’90s, hip-hop’s influence drifted south to P.R., where artists picked up the form and content of gangsta rap but tweaked the sound with regional touches.

KEY PLAYERS The scene’s biggest figure is Tego Calderon, whose 2003 CD, El Abayarde, has sold 500,000 copies so far. Ivy Queen is one of the few women in the genre; Don Omar and Hector y Tito are also worth seeking out.

ESSENTIAL ALBUMS Dancehall Nice Again 2004 (Sequence) boasts a handful of hot reggaeton cuts; Calderon’s El Enemy de los Guasibiri (White Lion) is all muscular rhymes and sinewy beats, while Ivy Queen’s new Diva Platinum Edition (Real Music) is stuffed with catchy hooks and sticky grooves; it’s our No. 1 pick for crossover success on these shores.

NECESSARY ACCESSORY ”Don’t go to a reggaeton club all dressed up and expecting salsa-style couples dancing,” says Tony the Tiger, assistant program director at Power 96 in Miami, where they’ve begun playing reggaeton alongside English-language hip-hop, dancehall, and R&B. Instead, you’ll see casual U.S.-style hip-hop gear, meaning jerseys, jeans, and jewelry.