Those familiar with Rod Stewart's later career might be surprised to find his name in this context, but early in his career he was certainly one of the greatest rock singers. Stewart represents to me more wasted potential than just about any other performer I can think of.
Here with the Jeff Beck Group on their 1968 debut album Truth with Bonnie Dobson's "Morning Dew."
Here's the title track from Stewart's second solo album, Gasoline Alley, released in 1970. The writing credit is to Stewart and his long-time collaborator Ronnie Wood, later of the Rolling Stones.