SEVENTEEN YEARS after its third single, “My Generation,” became a hit in Britain and went on to become the band’s signature song and 15 years after its first tour of the U.S., the Who has embarked upon what’s being described as its “farewell tour.” Or possibly its farewell tour. [Either way, the quartet will continue to record; the members are just tired of hitting the road.]

At any rate, there’s nothing like talk of a “last waltz” to whip up a frenzy of sentiment, and anticipation ran predictably high Tuesday night at Rosemont Horizon, where the veteran British band kicked off two nights of shows. “This night will end, but the memory will last forever; long live the Who,” proclaimed the scrawl on a banner displayed by one fan [a banner second only in heartfelt sincerity to the one reading “These seats s–k,” displayed by fans at the very back of the arena].

Whether or not the memory of Tuesday night’s concert “lasts forever” — the band, in fact, has given more memorable shows in previous years, though its current efforts are certainly powerful enough—the Who’s place as one of rock’s most enduring and affecting bands is assured. In the beginning, it was songwriter Pete Townshend’s guitar-smashing gimmick that attracted attention to the quartet as much as anything else, and the band has always been known for its energetic live shows. But by the late 1960s, “Tommy”— the concept album about the deaf, dumb and blind kid who “sure plays a mean pinball”—had proved the band one of pop’s major contenders on a strictly musical level as well.

IN THE ENSUING years pop fads have come