Few bands in the history of rock & roll were riddled with as many contradictions as the Who. All four members had wildly different personalities, as their notoriously intense live performances demonstrated. The group was a whirlwind of activity, as the wild Keith Moon fell over his drum kit and Pete Townshend leaped into the air with his guitar, spinning his right hand in exaggerated windmills. Vocalist Roger Daltrey strutted across the stage with a thuggish menace, as bassist John Entwistle stood silent, functioning as the eye of the hurricane. These divergent personalities frequently clashed, but these frictions also resulted in a decade's worth of remarkable music.

As one of the key figures of the British Invasion and the mod movement of the mid-'60s, the Who were a dynamic and undeniably powerful sonic force. They often sounded like they were exploding conventional rock and R&B structures with Townshend's furious guitar chords, Entwistle's hyperactive bass lines and Moon's vigorous, chaotic drumming. Unlike most rock bands, the Who based their rhythm on Townshend's guitar, letting Moon and Entwistle improvise wildly over his foundation, while Daltrey belted out his vocals. This was the sound the Who thrived on in concert, but on record they were a different proposition, as Townshend pushed the group toward new sonic territory. He soon became regarded as one of the finest British songwriters of his era, as songs like "The Kids Are Alright" and "My Generation" became teenage anthems, and his rock opera, Tommy, earned him respect from mainstream music critics.

The Who began to fragment after the release of Quadrophenia, as Townshend began to publicly fret over his role as a rock spokesman; in private, he began sinking into alcohol abuse. Entwistle concentrated heavily on his solo career, including recordings with his side projects Ox and Rigor Mortis, as Daltrey alternately pursued an acting career and solo recordings. Moon, meanwhile, continued to party, celebrating his substance abuse and eventually releasing the solo album Two Sides of the Moon, which was studded with star cameos. During this hiatus, the group released the rarities collection Odds and Sods. Meanwhile, Townshend continued to work on songs for the Who, resulting in the disarmingly personal The Who by Numbers in 1975. The record and its accompanying tour became a hit, but following the tour's completion, they officially took an extended hiatus. The Who reconvened in 1978 to release Who Are You. Instead of responding to the insurgent punk movement, which labeled the Who as has-beens, the album represented the group's heaviest flirtation with prog rock since Quadrophenia. The album became a huge hit, peaking at number two in the American charts and reaching platinum. Instead of being a triumphant comeback, though, Who Are You became a symbol of tragedy, since Keith Moon died of a drug overdose on September 7, 1978, mere months after the record's release. Since Moon was such an integral part of the Who's sound and image, the band had to debate whether continuing on was a wise move. Eventually, they decided to continue performing, but all three surviving members would later claim that they felt the Who ended with Moon's death.

Hiring Kenny Jones, a former member of the Small Faces, as Moon's replacement, as well as keyboardist John "Rabbit" Bundrick to round out the lineup, the Who began working on new material in 1979. Before they released a new record, they released the live documentary The Kids Are Alright and contributed music to Franc Roddam's cinematic adaptation of Quadrophenia, which starred Phil Daniels. The Who began touring later in 1979, but the tour's momentum was crushed when 11 attendees at the group's December 3, 1979 concert at Cincinnati's Riverfront Coliseum were trampled to death in a rush for choice festival seating. The band wasn't informed of the incident until after the concert was finished, and the tragedy deflated whatever goodwill they had.

Following the Cincinnati concert, the Who slowly fell apart. Townshend became addicted to cocaine, heroin, tranquilizers and alcohol, suffering a near-fatal overdose in 1981. Meanwhile, Entwistle and Daltrey soldiered on in their solo careers. The band reconvened in 1981 to record and release Face Dances, their first album since Moon's death. The album was a hit but received mixed reviews. The following year, they released It's Hard and embarked on a supporting tour billed as their farewell to fans. The live Who's Last was released in 1984 as a commemoration of the tour.

The farewell tour didn't turn out to be the final goodbye from the Who. While Entwistle and Daltrey slowly faded away, Townshend continued recording to relative success. However, the Who still haunted him. The group reunited to play Live Aid in 1985, and three years later, they played a British music awards program. In 1989, Townshend agreed to reunite the band, with Jones being replaced by session drummer Simon Phillips, for a 25th anniversary tour of America. Whatever goodwill the Who had with many fans and critics was squandered on that tour, which was perceived as simply a way to make a lot of money. The Who reunited again in 1994 for two concerts to celebrate Roger Daltrey's 50th birthday. Following the success of his Broadway adaptation of Tommy, Townshend decided to revive Quadrophenia in 1996, reuniting the Who to perform the piece at the Prince's Trust concert in Hyde Park that summer. The Who followed it with an American tour in the fall, which proved to be a failure. The following summer, the Who launched an oldies tour of America which was ignored by the press. In October 2001, they played the Concert for NYC benefit for families of the victims of the Sept. 11 attacks. In late June, 2002, The Who had once again regrouped and were about to kick off a North American tour when John Entwistle died at the age of 57 in Las Vegas' Hard Rock Hotel.