Conversation so far:
When did Bob Welch join Fleetwood Mac?
1971
What was Bob Welch (musician) role with Fleetwood Mac?
Guitarlead and backing vocals
Was Bob Welch (musician) successful?
He had a successful solo career in the late 1970s.

Question: What was the song?
Self-contained rewrite: What was the songs that bought Bob Welch (musician) success?