Glen Campbell was one of the famous guitarists of the wrecking crew, the LA session musicians. He was so talented he moved on to making his own music.
Glen was the only member of The Wrecking Crew who couldn’t read sheet music. That’s unheard of for a studio musician. Heck, their job description is pretty much being able to play sheets perfectly by the second take. Glen could listen to any composition once and instantly write a guitar part in his head then play it by ear. A real musical prodigy.