40. "Blue Letter"
"Blue Letter" was written by Michael and Richard Curtis, two brothers who met Buckingham and Nicks during their pre-Mac Polydor days. The four musicians cut two demos together: "Blue Letter" and "Seven League Boots" (which Crosby, Stills and Nash later reconfigured as "Southern Cross"). Fleetwood Mac decided to record "Blue Letter" at the last minute, as they were finishing work on their self-titled '75 LP. "The idea came to us literally on the spot," wrote Fleetwood. "The Curtis brothers were recording demos at Sound City, and when we heard them play the song, we decided to give it a go."