Bob Geldof (search) makes an unlikely saint. The rangy, foul-mouthed Irish rocker who fronted the Boomtown Rats (search) in the 1970s is now far better known as a champion of Africa, haranguer of the powerful and organizer of star-studded charity concerts.

British newspapers once called him Bob the Gob. Now, with just a touch of irony, he's Saint Bob.

Geldof, 53, was first anointed when he organized the 1984 Band Aid single and the Live Aid concerts the next year, which raised millions for famine relief in Africa. Twenty years later, he's behind Live 8, a series of concerts around the world designed to press leaders of the rich G8 countries to relieve the burden of impoverished African nations.

Announcing the concerts last month, Geldof said the G8 meeting in Scotland (July 6-8) provided a "unique opportunity for Britain to do something unparalleled in the world ... to tilt the world a little bit on its axis in favor of the poor."

If Live Aid was about fundraising, he said, Live 8 (search) is about awareness-raising, "not for charity but for political justice."

In the early 1980s, Geldof was known as a talented but prickly musician, who took the Rats' name from a song by socialist folk singer Woody Guthrie but boasted that he'd gone into music "to get famous, to get rich and to get laid."

Then he saw a television report about famine in Ethiopia and decided he had to act. With Midge Ure of Scottish band Ultravox, Geldof wrote the song "Do They Know It's Christmas?" and persuaded the era's top British acts — including Sting, U2, Boy George and Duran Duran — to perform it under the name Band Aid.

Released before Christmas 1984, the song sold 3 million copies and inspired a U.S. single, "We Are the World."

Live Aid — staged in London and Philadelphia in July 1985 — raised $80 million for famine relief, and featured performances by Paul McCartney (search), Queen (search), U2 (search) and Phil Collins (search), who crossed the Atlantic by supersonic Concorde to play at both shows.

For Saturday's Live 8 concerts, Geldof once again coaxed and cajoled the cream of the pop world — including Elton John (search), Madonna (search), R.E.M. (search), Coldplay (search) and a reunited Pink Floyd (search) in London; Jay-Z (search), Maroon 5 (search) and Stevie Wonder (search) in Philadelphia; Dido (search) in Paris and Bjork (search) in Tokyo — into appearing for free.

With his unruly mane of hair — once dark, now gray — and direct manner, Geldof's passion remains strong. Yet he is a contentious figure.

Some have criticized his support for fathers' rights groups and opposition to the European single currency. Many were puzzled when he said President Bush (search) "has actually done more than any American president for Africa."

Nor is Live 8 universally praised. Blur's Damon Albarn criticized the lack of black artists at the shows, and others say Live 8's call for G8 leaders to double aid, cancel poor countries' debt and rework unfair trade laws may do more to reward corrupt African governments and salve Western consciences than to relieve poverty.

Oasis songwriter Noel Gallagher — not performing at Live 8 — said he was skeptical that "one of these guys from the G8 is on a quick 15-minute break at Gleneagles and sees Annie Lennox singing 'Sweet Dreams' and thinks ... 'She might have a point there, you know?'"

Geldof is reluctant to analyze his motivations. But others have studied his biography, scarred by loss, for clues to his intensely driven personality.

Geldof's mother died of a brain hemorrhage when he was 7. His longtime partner Paula Yates, mother of his three daughters, died of a drug overdose in 2000. Geldof has raised their children, Fifi, Peaches and Pixie, and also adopted Heavenly Hiraani Tiger Lily, Yates' daughter with the late INXS singer Michael Hutchence.

Born in an Ireland he recalled as dull and repressive, Geldof soon escaped to a music career — initially as a rock journalist in Canada.

Returning to Ireland in the mid-70s, he formed the Boomtown Rats, whose reggae-inflected sound and edgy lyrics caught the emerging punk mood. The band scored several British hits — the snarling "Rat Trap" knocked John Travolta and Olivia Newton-John off the top of the charts in 1978.

Described by Geldof as "perennial outsiders, antiestablishment and anti the antiestablishment," the band is best known for having its song about a high school shooting rampage, "I Don't Like Mondays," banned by many U.S. radio stations.

By the early 1980s, the Rats' fame was in decline. Geldof continues to produce solo records, but is now far better known as a campaigner. He seems to accept that will be his legacy.

Geldof has said he is proud of his musical legacy, but told a reporter in 2003 that he'd been awed to meet people like McCartney and Mick Jagger, "because they're ... amazing artists and ... well, I'm not."