Musician Mike Campbell is shedding some light on his complicated friendship with the late Tom Petty.

As a founding member of Tom Petty and the Heartbreakers, Campbell had a front-row seat to the singer’s career as he helped the rock group cement their place in music history with such hits as “American Girl” and “Learning to Fly.” In his new book “Heartbreaker: A Memoir”, Campbell details how he witnessed the darker periods in Petty’s life and felt too powerless to intervene.

“You couldn’t talk Tom into anything,” Campbell says of the rock icon, who died of an accidental drug overdose in 2017.

Campbell’s new book, Heartbreaker: A Memoir, recounts his experience as the lead guitarist of Tom Petty and the Heartbreakers, from the band’s 1976 inception to Petty’s death in 2017. The book hits shelves on March 18.