NEW YORK – If you have very young friends or relatives who are curious about the development of rock 'n' roll music, you can painstakingly detail rock's 25-year history. Or you can save yourself the trouble and take them to a Who concert.

The Who, which on Thursday started the first of five concerts at Madison Square Garden, are explosive and energetic as ever. Despite the passage of 15 years and the loss of one of rock's premier drummers – Keith Moon, The Who are still what rock 'n' roll is all about.

With the arrival of disco and the passage of years, rock 'n' roll fans have adopted a defensive posture that embraces virtually any rock act. And so now there is a glut of bands whose punk posturing and pseudo-intellectual inanities fill the FM air waves, and a pack of disc jockeys falling over themselves to proclaim these groups' worth. Such bands frequently become established after one record, even if their music represents slight variations on old rock riffs and if 90 percent of them are lyrical illiterates.

And although many rock fans gleefully buffoon the artificial practices of the disco set, rock has developed its own set of stale rituals. The acts have often relied upon visual gimmicks or a contemptuous sneer toward their audience, who in turn use the concert to vent hostility. The crowd invariably lights matches to proclaim the group's brilliance – no matter what the quality of the performance.

Drugs have become a secular communion at concerts; their numbing effect on the mind is the only explanation I can think of for the blind fanaticism surrounding groups like The Grateful Dead.

Thursday's Who concert was not without its reminders of why I had attended very few rock concerts in recent years. Although the concert was scheduled for 8 p.m., technicians worked to about 8:45 p.m. testing the amplification and adjusting the lights. Why can't this ever be done beforehand? Additionally, a trip to the men's room while waiting for the concert to start produced two direct drug pitches.

Once the music finally began, however, The Who wiped the slate clean and allowed the talent to do the work. There was a frenzied Pete Townshend, still delighting the crowd with his windmill style of guitar playing, powerfully slashing out chords. A trimmed Roger Daltrey, whose voice has improved markedly over the years, frequently paced in circles when not singing, and bassist John Entwistle was dressed like a mid-60s mod. The group went out of its way to include new drummer Kenney Jones, who is highly competent but who lacks the passionate fluidity of the late Moon.

And by mentioning Moon while introducing "The Music Must Change," Townshend provided the fans an opportunity to give the deceased drummer a roaring tribute.

Without spitting fire or sleazy costuming, they had a highly appreciative, full-house crowd at a fevered pitch. At one point, after "Pinball Wizard" and the

THE WHO PERFORM AT MADISON SQUARE GARDEN THURSDAY ...(l.-r.) John Entwistle, Roger Daltrey, Pete Townshend, Kenney Jones

"See Me, Feel Me" sequence from "Tommy," the house lights were turned on to illuminate a roaring jubilant crowd, who were immediately taken by their own awesomeness. My, my, what would the Ayatollah say?

The group mixed their repertoire well, from "Substitute" and "My Generation" to selections from their last album, "Who Are You," unifying an audience with a substantial age range. Although the technical performances were not especially dazzling, they were fine enough to showcase the Who's dazzling songbook.

There seemed to be little rowdiness; the music was too good to waste time throwing cherry bombs. In fact, the crowd's thunderous responses – at a level I have never heard – played an important part in the concert's overwhelming success.

And although there was the usual anti-disco sentiment ("Kill the Bee Gees" read one T-shirt), the Who's performance made such comparisons moot. Who needed to worry about disco with this on stage?

I was never really a big Who fan, although I respected Townshend's drive and relentlessly played "Tommy" a decade ago. But they have won my admiration over the years, and now, after the Garden concert, an unabashed enthusiasm. The Who are living explanations of rock's greatness.