There was a lot of pressure on Fleetwood Mac when they started recording Tusk in late 1978. Their last album, Rumours, was about as big as a rock record could be. Topping it would be impossible, and most any effort would seem like a disappointment. They were also going through intense personal problems and had enough leverage to go crazily over budget. The result was an album that cost over $1 million (an industry record) and filled up two LPs. Many see it as their White Album since the tone varies wildly from song to song and it comes across almost like a collection of solo songs. It's also a complete masterpiece, probably the greatest thing they ever created. The label was pissed off they made such a sprawling, uncommercial album – but that's hardly surprising.
The most commercial-sounding track on the album is the Stevie Nicks ballad "Sara." Unsurprisingly, it was the biggest hit from the project, landing at Number Seven on the American Hot 100. Nicks originally wrote the song about the group's endless personal problems but eventually changed the lyrics to make the song more universal.