Greatest Hit (...And 21 Other Pretty Cool Songs) is a compilation album by American progressive metal band Dream Theater, released in Australia on March 29, 2008, and by Rhino Records in the United States on April 1.

It features three songs from their breakthrough album, Images and Words, remixed by Kevin Shirley: "Pull Me Under," "Take the Time," and "Another Day."

The compilation also includes "To Live Forever," a re-recording from the Awake era of a song originally from the Images and Words sessions (previously featured as a B-side of the single "Lie"), which had not been released on a full-length album.

Drummer Mike Portnoy explained in the album's booklet that the song selection was carefully curated to appeal to both new listeners and longtime fans.

The compilation offers alternative versions of songs from previous albums to entice newcomers to explore the band's catalog while providing existing fans with fresh takes on familiar tracks.