Patti Smith and Yoko Ono are among 99 artists contributing 99 tracks for the Occupy This album, raising funds for the Occupy Wall Street Movement.

The album, launching in physical and digital form on May 15, features previously unreleased tracks by a host of stars including Willie Nelson and Ani DiFranco. A night of special performances by participating artists is also set to take place, on May 8 at The City Winery in New York.