Mule Variations  by Tom Waits

In 1999, Tom Waits released the thirteenth album of his career. Mule Variations is one of the most important milestones in Tom Waits' discography, combining his experimental flair with a return to his roots. Waits described the album's sound as "sur-rural" (surreal-rural). The style is a blend of delta blues, gospel, avant-garde experiments, and industrial sounds, while ballads are also present.

Mule Variations was recorded in 1998 at Prairie Sun Recording Studios in Cotati, California. Waits chose this studio (a former chicken farm) for its rural and "dusty" atmosphere. Although some digital elements were used, the album stands out for its analog sound, with recordings that included even external noises or banging on furniture for percussion. Almost all the songs were written by the duo of Waits and Brennan. The production was handled by Tom Waits himself, along with his wife and long-time collaborator, Kathleen Brennan.

This album was his first release through the independent label ANTI-. Mule Variations won the Grammy Award for Best Contemporary Folk Album, while the song "Hold On" was nominated for a Grammy for Best Rock Performance. The album achieved significant success, selling over 500,000 copies worldwide and reaching No. 30 on the Billboard 200.