The man behind the smile

"I have been privileged to document one of the great stories in the history of mankind," says David Leaf, the writer and director of Beautiful Dreamer: Brian Wilson and the Story of Smile. The film is a revealing psychological portrait of Wilson, the genius behind The Beach Boys, and Smile, his legendary album that was left unfinished for 37 years. "There is no parallel of an artist creating something at the peak of his powers, abandoning it, and then returning to it nearly four decades later to complete it brilliantly," Leaf adds.

"I have been privileged to document one of the great stories in the history of mankind," says David Leaf, the writer and director of Beautiful Dreamer: Brian Wilson and the Story of Smile. The film is a revealing psychological portrait of Wilson, the genius behind The Beach Boys, and Smile, his legendary album that was left unfinished for 37 years. "There is no parallel of an artist creating something at the peak of his powers, abandoning it, and then returning to it nearly four decades later to complete it brilliantly," Leaf adds.

In the film, Leaf, who is a close friend of Wilson, follows him for six months in 2003-4, as he prepares to revive the album live for its world premiere at the Royal Festival Hall, in London. "One of the great ironies of the whole long process was that the most famous unfinished record had its debut as a live musical event. Who could have imagined that happening?" Leaf says.

In a series of candid interviews, Wilson discusses his mental health and drug use over the years and the courage it took to re-engage and complete what he had set out to do all those years ago. There is footage of a terrified Wilson alone backstage, moments before his performance of Smile, reflecting on how "California Girls" came to him while he was on an LSD trip. There are interviews with his collaborator, Van Dyke Parks, who reappears to help complete Smile, cameo interviews with industry greats such as Sir George Martin and Elvis Costello, and archive material, including Wilson's performance of "Surf's Up" from a 1967 CBS News special hosted by Leonard Bernstein.

Leaf first got to know Wilson in the late 1970s when he was working on The Beach Boys and the California Myth. "Over the course of 15 years, we got closer," says Leaf. "The hardest part for me came in early January 2004. Brian was clearly unhappy. He walked out of rehearsals to admit himself to hospital. The last thing I wanted to do was make a film about Smile and Brian. But Brian was very determined to do it, despite the pain and the memories."

What memories? "As an artist in the 1960s he had been able to overcome all obstacles to create a body of work that put him toe-to-toe with The Beatles," says Leaf. "To create art at that level you must have a belief in yourself, and then when he was met with resistance - perhaps because it was too avant-garde and the band questioned his vision - self-doubt crept in. He also lost momentum because he got sick. It took baby steps and an enormous amount of unconditional love and support to get him back to a place to be creative again."

For Leaf, the tensest day was when Brian came to watch the film. "Watching his life unfold in front of his eyes at a time when he was younger and when his life, artistry and career fell apart, is very intense," says Leaf. "But he has told me he loves it. There is not a moment that doesn't hold your interest."

'Beautiful Dreamer: Brian Wilson and the Story of Smile', ICA Cinema, London SW1 (020-7930 3647; www.ica.org.uk) 10 to 30 Dec