Led Zeppelin has been called the grandfathers of the "Heavy Metal" genre. At their height in the early to mid 1970s, they frequently outsold the Rolling Stones in concert tickets. And by 1973, they had sold more albums than any other band worldwide. Their anthemic song, "Stairway to Heaven," is the most-played song in the history of radio.

Led Zeppelin was formed out of the ashes of the 1960s supergroup The Yardbirds, once featuring renowned guitarists Eric Clapton and Jeff Beck, and later, a young studio session guitarist, Jimmy Page. (Page, it is estimated, played on 50 to 90 percent of the popular rock records made in England from 1963 to 1965.) In 1965, he joined the Yardbirds, having turned down an offer to replace Eric Clapton just a year earlier. With the Yardbirds, Page and fellow guitarist Jeff Beck pioneered the two-guitar style of rock. Beck left only a year later, however, to...