Not since the British invasion of 1963-64 has a new sound taken over American music the way disco is doing now. The disco beat dominates the car radio; 12-inch disco singles claim the front racks in record stores; slinky disco clothes shine in store windows; disco palaces pop up in shopping centers far out in the suburbs.

The Bee Gees, Village People and Donna Summer are not only in the top 10 but on magazine covers and television shows everywhere. Even established rock acts like Rod Stewart, Marvin Gaye and the Beach Boys feel compelled to release disco singles to get back into the marketplace.

At the same time, no music since the earliest rock 'n' roll has inspired the kind of backlash that disco has suffered. At rock concerts now, it seems every fourth person is wearing a T-shirt with an obscene, antidisco slogan on it. Meanwhile, backstage the performers are dreaming up new put-downs of disco for interviewers.

If one listens to the records, however, disco hardly seems worth all the fuss. It's simple, harmless dance music that's unlikely to either ruin or revolutionize popular music. Most of the music is mediocre; the best of it has the irresistible energy of any perfected pop form. The most important pop music of any era, however, is seldom the music that sells the most. Disco is not the music of this era that will last.

Disco music is for dancing, not listening. This sounds terribly obvious, but people who don't dance can't conceive of records designed for something other than listening. Concert orr listening records have enjoyed a rare dominance of the pop charts over the past 12 years. Now that dance records are staging a long overdue comeback, the nondancers are feeling dispossessed on the radio band.

Even if you do dance, though, you won't necessarily like disco. Tastes in dancing vary as much as tastes in listening, and disco is very conservative dance music. Disco is defined by a skidding, airy momentum over an emphatic, unvarying beat. The absolutely steady beat encourages precise, predictable movements, while the breezy flow encourages sweeping, unpunctuated motion.

This minimalist music allows for a kind of perfection in dancing. With the variables reduced to a predictable few, flawless execution becomes a realistic goal. For people like Tony Manero, the dynamic loser of "Saturday Night Fever," absolute mastery of something-anything-can be a keen satisfaction.

The Bee Gees' "Spirits Having Flownc (RSO S1-3041) is one of very few discco albums to hold up cut after cut. Like their predecessors in sould music, disco artists are oriented to the one big single rather than a larger consistent body of work. As a result, most disco albums are one or two catchy hits surrounded by filler. Any disco artist who can put as many as three standout songs on one album qualifies as a major figure in the field.

The Bee Gees have at least six strong cuts on their new album. The balladic "Too Much Heaven" (recalling the earlier "How Deep Is Your Love") and the uptempo "Tragedy" (recalling the earlier "Stayin' Alive") have already been hits."Search, Find" (recalling "You Should Be Dancing") and "Love You Inside Out" (recalling "More Than a Woman") should follow.

As these comparisons imply, the Bee Gees have chosen to duplicate their precedent-shattering success of the "Saturday Night Fever" soundtrack. Despite a few missteps-the faked funk of "Boogie Child" and the ponderous title cut-they do.

While most disco producers have been too preoccupied with the mechanical beat and airy momentum to pay much attention to melody and harmony, the Bee Gees have managed to keep all four elements perfectly integrated. They haven't been able to go further and add secondary themes or emotional depth, but they're already far ahead of everyone else.

Besides the Bee Gees, Bernard Edwards and Nile Rodgers of Chic are among the few disco acts to produce their own records. As a result, their music has a real personality, in contrast to the increasing anonymity of disco music. "C'est Chic" (Atlantic), Chic's second album, coontains a good bit of filler but also three or four very likeable hits. The lyrics are mindless, but the verse rhythms wind tighter and tighter till released in a revivalist shout of "Freak Out!" or in the comforting church bells of "I Want Your Love."

Gloria Gaynor and Amii Stewart weren't able to put more than one strong sond on their albums. Gaynor's "Love Tracks" (Polydor PD-1-6184) contains her No. 1 hit, "I Will Survive," and seven other cuts with the combination of Southern soul and disco but without the hook.

Stewart's "Knock on Wood" (Ariola SW 50054) contains the Star Wars synthesizer on her hit version of Eddie Floyd's recycled soul song. It also contains seven other songs with the synthesizer but not the composition.

Gaynor and Stewart are typical of many of the artists who will disappear with the inevitable decline of disco. Disco is sure to survive in some form, but only the strongest artists-the Bee Gees, Chic, Donna Summer-are likely to evolve with it.