He is considered one of the pioneers of the concept of album cover art.
In the 1960s and 1970s, he designed covers for many rock stars, such as Mama Cass, Crosby, Stills, Nash, and Young, Joni Mitchell, The Doors, The Eagles and Jackson Browne.
He created album covers for Neil Young for 35 years.
In 2000 they made a documentary California Rock: Under the Covers, depicting their album cover works and participation in the Los Angeles rock scene.
[7] He was married to Annie Burden, who is one of the "Ladies of the Canyon" in the Joni Mitchell song.