The frontier in modern dance these days lies straight behind us. Exploring the past seems as daring as discovery of the new. Last night, in Kennedy Center's Terrace Theater, Annabelle Gamson showed why she is one of the bravest of current adventurers -- she danced to Chopin, Brahms and Scriabin in the guise of Isadora Duncan, mythological first of all moderns.

Dressed in tunics or robes, her body heavier than when she started on this trail, wearing her long white hair loose or coiled at the neck, Gamson has grown to resemble Isadora in all but the features. Isadora's dances, taught her by Julia Levien, are as deceptively simple as beginnings ought to be. She skipped, ran and marched. She rocked gently back and forth. She stretched or dropped to the floor. The only things Isadora did to hide her weighty body were to keep the arms firm and afloat, the eyes peering into the light, and the musiciality cleanly free -- so Gamson would have us believe.

Isdora Duncan died in 1927, and very few people know whether Gamson's impersonation is the Athenian original or a Roman copy. If the latter, yesterday's performance was still a treat. Tonight and tomorrow, Gamson becomes the German Sybil, Mary Wighman.