Donovan helped initiate the ’60s psychedelic revolution with his number-one hit “Sunshine Superman.” To commemorate its 50th anniversary, the Scottish singer, songwriter, and guitarist is touring America – including a June 10 stop at the Adler Theatre.

The backing musicians on the single (and the album that shares its name) included Jimmy Page and John Paul Jones shortly before they formed Led Zeppelin. Donovan discussed these matters as well as his friendship and interactions with the Beatles in a recent e-mail interview.