Rarities & B-sides (Delerium album)

Rarities & B-sides is a 2015 compilation album with previously unreleased tracks and remixes by Delerium from the last 15 years. The first single "Glimmer" was released in January as an EP with some extra remixes. Two other new songs are included; "Aurora" featuring Swiss-Canadian vocalist Rykka and "Ray" featuring Kristy Thirsk.

Bill Leeb said about these three tracks: "These songs were literally buried in a box of tapes for more than 10 years and were accidentally unearthed by our sound engineer Greg Reely. “Aurora” having been buried in the shuffle of all of the Music Box Opera demos, is unique. The music itself goes back several years but the vocals were done more recently, so it is truly a blend of the past and the present."