Thirty-five years after Pink Floyd released "The Dark Side of the Moon," Roger Waters finally has come to grips with his own dark side.

"Things do change," says Waters, 64. "We all have to own up to the fact that we carry a dark side. I'm very happy to stand up and say, 'Mea culpa.' "

This wasn't always the case. For years, Waters had a reputation as rock's biggest misanthrope. When "Dark Side" catapulted Pink Floyd into arenas in the '70s, the singer-bassist grew to hate performing live. More than once, he spat on fans who dared to yell out song requests.

"That's true," he says. "I was deeply angry and unformed. And I was hypercritical of the way audiences were at rock shows, which provided the first inklings of 'The Wall' and the idea of building a wall to cut the audience off."

"The Wall" (1979) became Pink Floyd's best-selling album. But the title symbolized the barrier he built between himself and drummer Nick Mason, keyboardist Rick Wright and singer-guitarist David Gilmour.

He wrestled creative control from the others on "The Final Cut" (1983) and quit the group two years later. When Pink Floyd carried on without him, he unsuccessfully sued to keep them from using the band's name.

The bad blood simmered through the '90s. But Waters eventually gave up his grudges after reading studies of how the brain works.

"I discovered the ego will invent memories that suit it," he says. "Like most rock 'n' roll bands that split up, there were terrible arguments in Pink Floyd about who did what and when. And it's a huge comfort now to know that nobody's memory is reliable. It ... explains a lot."

Another mellowing factor is his fiancee, filmmaker Laurie Durning: "I've got a good woman now and that's a big help," he says. "I've been saved."

In 2005, he buried the hatchet and regrouped with Pink Floyd to play London's Live 8 concert for global debt relief. The reunion ignited speculation about a worldwide tour. But like the recent Led Zeppelin reunion show, Floyd's gig may prove to be a one-shot deal.

"It was quite extraordinary, and I would do it again in a heartbeat," Waters says by phone from his home in New York. "I know Nick would, and I'm pretty sure Rick would. But I think Dave is largely disinterested in the idea. He's content to be on an island, which is fine. I applaud anyone who follows his gut feeling."

This summer, Waters is performing "The Dark Side of the Moon Live," a show he launched in 2006. In the first set, he plays solo songs and classics from "The Wall" and "Wish You Were Here." He devotes the entire second set to "Dark Side," Pink Floyd's mind-bending 1973 concept album about human nature and mortality.

All these years later, he's still taken aback by "Time," a song about realizing before it's too late how short life is. "What surprises me is that I wrote 'Time' when I was 29 years old," he says. "It was like a bolt of lightning going off in my head."