NEW YORK — Tom Petty’s family and former band members say it was like therapy to compile a four-disc box set of his music. It went on sale Friday, four days short of the first anniversary of his death.

Daughter Adria Petty says she felt that when Prince died there was no central place for people to grieve. She hopes “An American Treasure” provides that for Petty fans, as well as a document that reflects her father as a man, not just a hitmaker.

The younger Petty would hear her father’s music while walking down the street. She went to get her eyes checked, and her optometrist broke down in tears.

The project gave those close to Petty a way to deal with the enormity of the loss.

The Associated Press