Timeline is the second compilation album by Dutch progressive metal project Ayreon. It was released in November 2008 in Europe. It was also released in North America in early 2009. The album features three CDs containing selected songs from all Ayreon albums, and a DVD featuring live performances, video clips and behind-the-scenes. The third CD also feature an unreleased song, called "Epilogue: The Memory Remains", which provide further insight into the final chapter of the Ayreon concept and the probable future of its characters. Jasper Steverlinck, singer of Arid, guest appeared as the vocalist of the song. He would later be invited by Arjen to sing on his new side project Guilt Machine. Many songs were remastered for this release. Apart from the CDs and DVD, a timeline poster illustrating the Ayreon universe and a booklet containing new photos, lyrics, and notes on the story are also available in the Timeline package. Background Arjen A. Lucassen said that he hasn't released a compilation album before because he didn't want to reunite random chapters of a whole history in a single album. However, after connecting all other Ayreon releases in the album 01011001, he changed his mind and decided to create the album, which can be described as a timeline outlining the entire story. As the album will feature a summarized version of Ayreon's concept, one can deduce that the concept has come to an end. Therefore, concerning Ayreon's future, Arjen stated: "I don't see this as th