The reunion of Yes and Rick Wakeman comes at just the right time for all concerned. After erratic and self-indulgent solo flings, Wakeman and his four compatriots have finally realized that in unity there is strength - and popularity.

What happened to Yes during the two years that preceded "Going for the One" (Atlantic SD 19106), the newly released album that reunites the most successful of the group's several personnel configurations, was typical of the internal tensions that afflict successful rock 'n' roll groups. Not content to be members of a band that sells lots of records and concert tickets - and in the case of Yes, makes adventurous, ambitious classical-rock music - individual musicians get the itch to go out on their own and establish their own reputations.

That's what Peter Frampton and Boz Scaggs were able to do after leaving the moderately successful groups that they had been playing in - as second fiddles, so to speak. Others, though, haven't seen quite as lucky: David Clayton-Thomas eventually returned to Blood, Sweat and Tears, and the various members of the Allman Brothers Band have found that the popularity of their group doesn't insure immediate solo success.

In the case of Yes, Wakeman was the first to leave, and though his "The Six Wives of Henry VIII" was widely acclaimed, subsequent solo efforts seemed to be more historical extravaganza than pop music. By the time Wakeman got around to staging "The Myths and Legends of King Arthur and the Knights of the Round Table" on ice at a British rink, he was the butt of many a rock 'n' roll joke.

For the rest of Yes, the lesson was quicker and learned more easily. Patrick Moraz, who replaced Wakeman in 1974, decided to leave the group after his solo album received a warm criticial response; but once Jon Anderson, Steve Howe, Chris Squire and Alan White saw how indifferently the public greeted their various individual recording projects, it was back to the accustomed warmth and familiarity of the quintet.

Perhaps that is why "Going for the One" is the best Yes album in five years: Having got "the solo thing" out of their systems, these five musicians, all skilled and imaginative players, are once again ready to devote all their energies to a collective endeavor. It's like starting all over again, and in that sense "Going for the One" is a very impressive beginning.

For one thing, the music is more direct and energetic than it has been on recent albums. Although Jon Anderson still tends to indulge in bargain-basement mysticism in his murky and pointlessly obscure lyrics, the album's title tune has the punch and power that was missing from most of "Relayer," the group's last album of new material, released almost three years ago. Seve Howe's biting pedal steel guitar and Wakeman's honky tonk piano are particularly welcome touches.

But Yes, which will perform in concert tonight at the Capital Centre, is perhaps at its funkiest on "Parallels." Written by Chris Squire and built around his deep, thudding bass line, it features tight ensemble playing - even though it was recorded with Wakeman playing organ at St. Martin's Church in Veyvey, Switzerland, several miles away from his fellows, who were in a studio in Lausanne.

Wakeman also appears on church organ during "Awaken," a lengthy classical-rock suite in the tradition of "Siberian Khatru" and "The Gates of Delirium." Split into two sections, with a delicate Keith Jarrett-like piano solo by Wakeman as the dividing line, "Awaken" is musically more subtle than showcase pieces on previous Yes albums, and even Anderson's lyrics contribute to the pastoral mood.

These are encouraging signs of growth, indicators of a new maturity and seriousness on the part of the five Yes men. All five have obviously learned from their solo album debacles that it is their collective identity that must flourish if they are to remain successful musicians, and on "Going for the One" they have put into practice that lesson. Pop musicians rarely get an opportunity to correct their mistakes, but Yes, having been given a second chance, is not about to blow it.