Mickey Hart has followed the beat for half a century. It led him to San Francisco, where he played drums for almost 30 years with the Grateful Dead. To India, where he recorded the chants of the Tibetan exile Gyuto monks. To Indonesia, where he produced a new three-CD set of gamelan music, "Living Art, Sounding Spirit: The Bali Sessions." Lately, it's been bringing him to Washington.

When Hart arrived in town last month, it was with his band, Planet Drum, fresh from playing for the new and somewhat unsettling Woodstock Nation. But he was also taking meetings at the Library of Congress, where in May the psychedelic-rock veteran became a member of the board of trustees of the American Folklife Center. "I'm now involved in the digitization of the great sound archives at the Library of Congress," the percussionist says. "So I'm spending more and more time in Washington."

Hart is a high school dropout, but after years of simply hitting the drums--and taking "a lot of psychedelics," as he nonchalantly reports--he transformed himself into one of world music's most resolute autodidacts. "People might ask what the drummer of the Grateful Dead is doing on our board," admits American Folklife Center Director Peggy Bulger. "But when you start talking to Mickey, you realize he's extremely knowledgeable in ethnomusicology."

Hart's "most obvious asset is that he has access to another world, the commercial recording world," Bulger notes. But, she says with a laugh, "he has connections everywhere. I'm always amazed at who he knows. The Grateful Dead is just the beginning."

Bulger also extols Hart's passion, which is obvious backstage at Falls Church's State Theater a few hours before Planet Drum's July performance. Asked about his interest in rare and disappearing indigenous music, Hart talks almost nonstop for more than an hour. Although he says he's starving, the drummer barely takes time to punctuate his comments with bites of chicken satay from a Thai place down the street.

"Every day I try to listen to different music," he says. "I work out in the morning and I listen to the radio so I hear what's going on in popular music. And then all through the day I try to nip at different kinds of music from around the world. It helps me to relax. I find I keep getting drawn into indigenous musics. Popular music only goes so far for me. I can only listen to it for so long."

Hart is a vigorous 56, with only a few streaks of gray in his hair. His principal scar from the rock-and-roll wars seems to be his hearing. The drummer discourses in a semi-shout and frequently asks for questions to be repeated. But then he doesn't really need questions to prompt a wide-ranging discussion of the themes of his 1990 book, "Drumming at the Edge of Magic: A Journey Into the Spirit of Percussion" (written with Jay Stevens).

"Music is a mystery," he rhapsodizes. "Music is also what makes us human. It's like sex and love. It's one thing that we do share. It's not a luxury, it's a necessity really.

"Once I started researching 'Drumming at the Edge,' I realized what we were dealing with here. This is magic, this is the stuff of dreams. This is the great alchemy of life, where it was all contained."

In "Drumming at the Edge of Magic," which is in part a spiritual autobiography, Hart emerges as an amateur in the Victorian sense: a wealthy gentleman of leisure who pursues his scholarly interests with the help of a bevy of servants. It's just that in Hart's case the helpers are roadies, recording engineers and computer geeks rather than butlers, valets or native guides. When it's suggested that his quest for the world's sacred beats parallels 19th-century explorers' search for the source of the Nile, Hart apparently hears "Nile" as "grail."

"Yeah, like the grail," he says. "Well, it is the grail. It is a search and it is a journey and it is an adventure. I think of it in those romantic terms myself. I like that image. I can live with that image because that's what it's really like. You go into these great archives and you don't know what you're going to find, or you go out in the field and it is an adventure. I love the chase. I love to go out there."

Hart has subsequently published "Planet Drum: A Celebration of Percussion and Rhythm" (with Fredric Lieberman); his book of quotations about music, "The Spirit and the Sound," will arrive next month. He sends a roadie to fetch a mock-up of the latter book, and pages through it reading out loud his favorites--which is just about all of them.

In keeping with the Grateful Dead tradition, Hart blends musical scholarship with myth and mysticism. "Drumming at the Edge of Magic" draws heavily on the work of Joseph Campbell and accepts feminist archaeologist Marija Gimbutas's contention that "Indo-Europeans" wiped out the prehistoric world's idyllic matriarchal culture, thus rupturing the "intimate relationship between the drum and the goddess"--and creating Europe's painfully unfunky musical tradition.

The book also recounts Hart's encounter with a damaru, a Tibetan drum made from a child's skull. He believes the drum made him nauseated, and may have somehow been associated with an automobile crash he had. "It seemed pretty real to me back then. It seems pretty real to me now," Hart says. "There are powers in certain objects, and if you believe in those powers they're real. I still don't mess around with damarus."

Like so many of the connections between rock and world music, Hart's interest in non-Western styles was sparked when Indian musicians began visiting the newly psychedelized United States in the late '60s. "I met Alla Rakha, Ravi Shankar's drummer, and that changed my whole life," Hart remembers.

The visiting Indian musicians "didn't have money for PAs and stuff," he says. "And none of their music was recorded well. So I thought, I'll give them a little assistance. I'll go down there and give them a small PA and I'll give them the best recording they could ever get. I would just roll tape and I'd give them a copy of it. There was no money ever exchanged. And then I started to really fall in love with this music. It was like an affair that turned into something deeper than I had imagined."

At first, few of Hart's friends shared his enthusiasm for Indian, African and other non-Euro sounds. "I thought this was the most beautiful music in the world and my friends had to hear it," he recalls, but "I used to not even be able to give it away. I would give the recordings sometimes to a friend for a birthday or wedding gift or some special moment. I'd make a cassette of it for them. Sometimes they'd leave it on the table. They didn't even know what they were passing up."

From those spurned tapes, Hart's interest grew to archives like the American Folklife Center, whose predecessor agency was established in 1928. Bulger says the center has "the greatest collection of folk and world music in the world," but even that's not enough to contain Hart's quest. "I'm listening to Arab and Israeli music now and working at the archives in Jerusalem with Koranic and the Torah and those kinds of musics," he says. "It's a never-ending battle against time to preserve these musics.

"A lot of people say, why save these things? I say to them, after Picasso painted his great works what would you do? Throw them away? They bring beauty into the world. They're not just artifacts. They're pieces of all of our collective soul. They make it a better world.

"All over the world there are great archives that soon won't be," Hart continues. "We won't even be able to digitize them because of the decomposition. Remember that we've recorded on wax, tin, wire, acetate, magnetic tape, glass. You name it and we've imprinted it with sound. Now all these media are giving up at a rapid rate."

Hart's interest in digital technology isn't limited to preserving music. With Planet Drum, he plays an elaborate digital drum kit he calls RAMU (for "random access musical universe"). "It allows me to be a thunderstorm or a glass harp or a gamelan orchestra or whatever," he explains. "I have all these instruments that I've sampled over the years. I put them in my database, and now I call them up in the show. I'm able to change them at will. It's not dumb samples, it's really smart."

This technology puts Hart in the company of such rhythm-oriented contemporary electronic music groups as the Chemical Brothers and Loop Guru, whose music he endorses. He's less enthusiastic, however, about some of what he heard at Woodstock. "There was a certain kind of white-hot energy that was coming out of the crowd," he reports. "The bands were inciting to riot. It was like legal fighting out there, you know, like a cockfight. It was so un-Grateful Dead, and that's all I've ever known, pretty much."

Far from the belligerence of Woodstock '99, Hart recorded "The Bali Sessions" last March while on what he calls a vacation. "Usually on my vacations I record," he says. "That's normal for me. I love to do field recordings." The ex-Dead drummer describes Balinese gamelan music, a shimmering, intricate style played by troupes composed principally of tuned-percussion instruments, as "the absolute total favorite of mine for many years."

If there was any question of Hart's still being merely a hobbyist, it vanished when he asked local music scholar Ketut Gede Asnawa to suggest some of the best examples of recorded Balinese music. The man handed Hart a copy of "Music for the Gods," a CD compiled from archival recordings by the Library of Congress's Endangered Music Project. Surprised and pleased, acid rock's preeminent ethnomusicologist showed Asnawa the album's credit: Produced by Mickey Hart.