Between now and February 2005, Nonesuch plans to reissue the entire series -- 92 albums -- on CD's, beginning with its 13 African discs (which include ''Animals of Africa: Sounds of the Jungle, Plain and Bush''). The best of the batch are the meditative Nubian solo songs from Hamza El Din, the hypnotic Shona mbira (thumb-piano) music from Zimbabwe and the rip-roaring public celebrations from Uganda, Kenya and Tanzania that are modestly titled ''East Africa: Ceremonial and Folk Music.'' Place names have changed: Zimbabwe was Rhodesia, Burkina Faso was Upper Volta. But the albums, recorded from the 1960's into the 80's, have held up magnificently.

Ethnographic recordings were available well before Nonesuch started Explorer. Independent labels like Moses Asch's Folkways, in New York, and Le Chant du Monde, in France, were busily documenting what would later be called world music. They were fueled not by commercial prospects but by musical fascination and by the perpetual urgency of ethnomusicologists who feared that the styles they were recording would not last another generation.

Smaller labels, whose international recordings have been collected on the Yazoo Records series Secret Museum of Mankind, also sought out traditional music nearly as soon as portable recording equipment was available. It probably didn't hurt that traditional musicians wouldn't expect royalties.

A major label, Columbia Records, issued Alan Lomax's 18-volume ''Columbia World Library of Folk and Primitive Music'' in 1955, little realizing that its title would later be cringe-worthy. Elektra Records, the label that spun off Nonesuch, started as a folk-music label, and its fifth release, in 1954, was ''Voices of Haiti,'' recorded by the avant-garde artist and filmmaker Maya Deren. ''What could be more folky than the indigenous music of people?'' said Jac Holzman, who founded Elektra and Nonesuch and inaugurated the Explorer series. Explorer was named by the woman who ran Nonesuch, Teresa Sterne.

Most of the ethnographic recordings before the 1960's were lo-fi affairs -- a function of the available equipment -- with a specialist audience in mind. Folkways' initial archive of far-flung styles was recorded in mono, pressed on scratchy vinyl and packaged in utilitarian cardboard sleeves with highly academic notes mimeographed in fine print; it was aimed at libraries.

''I was interested in the wide variety of offerings that Moses Asch had gathered from around the world, but I was depressed by how tough the recordings were to listen to,'' Mr. Holzman said. ''I thought, I would love to hear more wedding music from the Sudan, but I would like to really hear it.''

He wasn't alone. The psychedelic late 1960's looked to foreign cultures as potentially enlightened alternatives. While hippies discovered Sufi poetry and the Upanishads, jazz and rock musicians looked into African and Asian (particularly Indian) music and collected non-Western instruments. (The lessons have continued ever since, lately with jam bands emulating and dance programmers sampling from a world of possibilities.)

Technology was also helpful. Battery-operated tape recorders were getting smaller and improving. David Lewiston, the musicologist whose Nonesuch Explorer album ''Music From the Morning of the World'' (which is to be reissued in January) was many listeners' first discovery of the monkey chant and gamelans of Bali, said he was lucky to find a battery-operated stereo tape recorder -- one of the first -- for $160 in Singapore on the way to Indonesia. When he got back to New York with his pioneering stereo recordings of Balinese music, he saw Nonesuch albums at a record store and sent a letter to the label, which asked him to bring in his tapes. The deal was clinched by the monkey chant: dozens of villagers bouncing the syllable ''chak'' back and forth in a frenetic crescendo.

The criterion Explorer brought to world music was pleasure, not duty. While the ethnomusicologists who collected the music were studying it, Nonesuch's releases were albums first and folkloric documents second. The African series includes not only traditional music but an album of ebullient Ghanian pop, recorded by a touring band in a New York studio.

The liner notes were respectful and informative but not overwhelming, calmly setting out exotic vignettes like this one from ''East Africa: Witchcraft and Ritual Music'': ''The initiation of a Taita girl into the tribe includes a secret ritual at night, during which the girl expects to be eaten alive by an animal in front of the elders; she has been led to believe that her remains will be reassembled at dawn.''

The packages were alluring, sometimes with poetic titles like ''A Bell Ringing in an Empty Sky'' (an album of Zen music for solo Japanese shakuhachi, a bamboo flute, due for rerelease in February 2004). With Explorer, world music was no longer forbidding or inscrutable, and the music came out of the library and into ordinary record collections. The series became a model for latter-day labels like Real World, World Village and the resurrected Smithsonian Folkways.

It took a little bit of Nonesuch's commercial savvy to let the broader public in on the beauty that had attracted the specialists in the first place. With the Explorer series, Nonesuch took a step that seems obvious only in retrospect: opening up the delights of world music by mingling the scholarly and the sensuous.