Led Zeppelin changed the course of rock 'n' roll. The mythic convergence of Jimmy Page's thunderous guitar pyrotechnics, Robert Plant's majestic screech, John Bonham's sledgehammer beat, and John Paul Jones' accomplished bass playing combined with lyrics that were alternately mystical and lascivious and created a harder, more epic rock sound than had ever been heard before and many would argue since.

At the same time, Led Zep raised the financial stakes of the modern record industy, thanks largely to manager Peter Grant, whose shrewd iron fist guided the band into becoming one of the most popular acts in rock history, selling over 50 million records. Those musical and financial extremes were matched only by the band's on-the-road antics, which set a prodigious standard for rock-star excess. Led Zeppelin originally rose from the ashes of Page's prior outfit, The Yardbirds, the British Invasion blues-rock group he joined in 1966 and which fell apart two years later. For the new cutting-edge combo he envisioned, Page recruited bassist/keyboardist/arranger John Paul Jones who, like Page, was a London studio veteran hired to play anonymously on numerous hits. When Page's original choices of vocalist and drummer -- Terry Reid and Procol Harum member B.J. Wilson, respectively -- proved unavailable, Reid recommended unknown 19-year-old Birmingham vocalist Plant. In turn, Plant suggested his hometown pal Bonham. The new quartet debuted in October 1968 under the name The New Yardbirds, fulfilling the old band's touring commitments in Scandinavia. Upon their return to England, they were re-christened Led Zeppelin, reportedly at the suggestion of Who drummer Keith Moon who predicted they would go over like a Lead Zeppelin. But the new band was consciously designed to be huge, and Grant scored the band an unprecedented mega-deal with Atlantic Records. The quartet's self-titled debut album, released in January 1969, instantly made it clear that Page and company had forged a genuinely audacious and original style out of a perversely personal amalgam of blues, folk and rock influences.

The quartet spent much of the next two years touring in America, where its stylistic fusion was generally dismissed by critics but enthusiastically embraced by fans and FM album-rock DJs. Released later in 1969, Led Zeppelin II showed considerable artistic development and featured the band's first full-blown anthem, "Whole Lotta Love"; to the surprise of many pundits but not to fans; the album hit the top of the Billboard's sales chart. The decisive commercial triumph of Led Zepplin II was significant for more than just its sales figures and chart numbers, though; it represented a changing of the guard as well as a changing of the times. And other events of that year served to underscore the shift: the Beatles were breaking up and three of rock's most charismatic icons -- Jimi Hendrix, Janis Joplin and Jim Morrison -- had died through various misadventures. Even though '69 was not yet over, the seventies had begun.

The band's creative momentum continued with Led Zeppelin III, which introduced the adrenaline-charged epic "The Immigrant Song" to the band's repertoire. But the album's most salient achievements were the graceful acoustic-based tunes that dominated Side Two, demonstrating just how decisively the band had transcended its original hard-rock tag.

Led Zeppelin's untitled (and frequently mistitled) fourth LP, released in 1971, sold 15 million copies and permanently established the group as the era's preeminent mega-band. The album boasted Zep standards like the pummeling "Black Dog," the starkly bluesy "When the Levee Breaks" and the idyllically hippieish "Going to California." But its centerpiece was the landmark epic "Stairway to Heaven," which still stands as the definitive classic-rock anthem of the 1970s, and the inspiration for a number of late-night teen epiphanies than the human mind can accurately process.

Houses of the Holy was an impressive follow-up, with standout tracks like the darkly foreboding "No Quarter," the ironically bubbly "Dancing Days" and the inventively reggae-inflected "D'yer Mak'er."

Despite Led Zeppelin's accelerated output -- five ambitious albums in as many years -- the band's work demonstrated a remarkable consistency and inventiveness. It was inevitable that the group wouldn't be able to maintain that pace -- or those lofty standards -- forever.

The group's 1973 American tour found the foursome more popular than ever, shattering the box office records that the Beatles had set in the previous decade. Grant got Atlantic to give Zeppelin its own custom label, Swan Song; their first release was the 1975 double album Physical Graffitti, featuring the epic "Kashmir," whose exotic eastern vibe reflected Page and Plant's fascination with Moroccan music. With Physical Graffitti and 1976's Presence, the band maintained its sales figures -- as did the live The Song Remains the Same, which doubled as soundtrack album to the concert film of the same name. But the music was beginning to show signs of strain.

In the second half of the '70s, the band was beset by a series of tragedies that seemed all too consistent with its longstanding aura of violence and black magic. In August 1975, Plant and his family were seriously injured in an auto crash while vacationing on the Greek island of Rhodes. In 1977, Plant's six-year-old son Karac died suddenly while the band was on tour in the U.S. The group then remained out of the public eye until 1980's In Through the Out Door, a subdued, melancholy effort that was mainly the work of Plant and Jones, since Page's and Bonham's struggles with heroin and alcohol, respectively, limited their input.

Led Zeppelin had completed some European dates and was preparing for a U.S. tour when, on September 25, 1980, Bonham died in his sleep, of alcohol-related asphyxiation. Rather than continue with a replacement, the band announced its breakup. The three surviving members did reunite a few times, including a set (with Phil Collins and Chic's Tony Thompson sharing drum duties) at 1985's Live Aid benefit; another for Atlantic Records' 40th-anniversary show at Madison Square Garden in New York City, with Bonham's son Jason manning the kit; for the younger Bonham's wedding; and on the occasion of Led Zeppelin's 1995 induction into the Rock and Roll Hall of Fame.

Still, Page, Plant and Jones largely distanced themselves from their former band's legacy during the '80s. Page released an underwhelming solo album and teamed with ex-Bad Company frontman Paul Rodgers in The Firm. Plant embarked on a productive solo career, initially refusing to play Led Zeppelin material live. Jones worked mainly behind the scenes, establishing himself as a busy producer, arranger and film-score composer.

In 1994, though, Plant and Page reunited for the mostly acoustic No Quarter, which gracefully reworked several old Zeppelin songs. The album's success led to a poopular tour and a more elaborate studio effort, Walking Into Clarksdale. Meanwhile, Led Zeppelin's vintage catalogue remains an irreplaceable cornerstone of classic-rock radio; their classic work remains so influential that, in 1990, a St. Petersburg, Florida radio station even attempted to launch an all-Zeppelin musical format.