Pete Townshend has always been rock ’n’ roll’s reluctant warrior.

The driving force behind the legendary band the Who, Townshend revolutionized rock with his guitar and pen. He wrote numerous anthems, including My Generation, See Me, Feel Me, Baba O’ Reilly and Won’t Get Fooled Again, and, when he wasn’t smashing guitars, embraced his role as the thinking man’s rock star.

At the same time, Townshend spent much of his life offstage trying to avoid all that came with his fame and fortune. While his bandmates — particularly the late Keith Moon and John Entwistle — enjoyed (and ultimately died from) sex, drugs and other excesses, Townshend sought out a spiritual path, only to fall short time and time again.

In Who I Am, Townshend’s long-awaited, deeply introspective memoir, he lays out his struggles with success, fidelity and fame. He pulls few punches in this exhaustingly detailed read, even though it doesn’t always paint him in the most flattering light. Like many alcoholics, he’s an egomaniac with an inferiority complex. “Artistic grandiosity” coupled with “desperately low self-regard” is how he prefers to describe it.

It’s those character traits, of course, that drove him to create groundbreaking music and take rock far beyond two-minute songs about cars, girls and surfing. It’s also what led him to constantly question his skills, success and place in the world.

Townshend traces his insecurities back to his childhood. Raised in post-World War II London by two hard-drinking musicians with marital issues, Townshend was sent to live with his deranged grandmother at age 6, and the scars are still visible.

“She was a perfect wicked witch, even occasionally threatening me with gypsy curses,” Townshend writes. He details being beaten and tormented by her and hints at even darker abuse.

Although he eventually returned to his parents, the damage was done. Townshend recalls that as a child he was most secure “in a gang of boys, protected by a dominant male.”

Perhaps he was foreshadowing his own role in the Who. He wrote the hits, but on stage it was tough-guy lead singer Roger Daltrey who brought the words to life. When the Who started to hit it big, Townshend’s self-doubt about his work and desire to do something groundbreaking grew. “I often felt that as a performing artist I was undervalued. … I wanted to be serious about what I did, and wanted my work — including smashing guitars in concert — to be regarded as part of a passionate commitment to an evolving stagecraft.”

He got all that with Tommy, the band’s acclaimed rock opera about a deaf, dumb and blind pinball champ who becomes a spiritual leader. Tommy, which was inspired in large part by Townshend’s painful youth, not only made the Who rich, it gave him the confidence to push the boundaries of music further with the band’s next two albums, Who’s Next and Quadrophenia.

Instead of enjoying his hard-earned success, Townshend often felt artistically trapped by the demands of feeding the machine that was the Who. He had long railed against hard drugs and tried to play the part of good family man. But in the end he turned to drink, drugs and women to escape his self-imposed hell, which shattered his marriage and nearly cost him his life.