Mousethief is surely right about "Babe I'm Gonna' Leave You". I can tell you a little more about it. Anne Bredon's college roommate later became an assistant to Joan Baez. One day she was singing "Babe..." and Baez said, "Who wrote that?" She ended up recording a beautiful version of the song.

About 20 years later, that same woman was playing her guitar and singing the song when her 14 year old son arrived home from school. Hearing the song, he said, "Hey, Ma, I didn't know you sing Led Zeppelin."

"This isn't a Led Zeppelin song," she told him, "Anne Bredon wrote this song. The kid laughed and went upstairs. He came back down with a Led Zeppelin album. Sure enough the song was on it (an awful version) with no writer's credit.

The woman called the record company. They told her that they had gotten it from the Joan Baez album and had thought it was traditional (the Baez album had no credit either, although Anne had received royalties). Anne ended up receiving more royalties from the Led Zeppelin album than she had ever gotten from the Joan Baez version.