Dream Theater is an American progressive metal/rock band formed in 1985 under the name Majesty by John Petrucci, John Myung, and Mike Portnoy while they attended Berklee College of Music in Massachusetts. They subsequently dropped out of their studies to further concentrate on the band that would ultimately become Dream Theater. Though a number of lineup changes followed, the three original members remained together along with James LaBrie and Jordan Rudess until September 8, 2010 when Portnoy left the band. In October 2010, the band held auditions for a drummer to replace Portnoy. Mike Mangini was announced as the new permanent drummer on April 29, 2011.

The band is well known for the technical proficiency of its instrumentalists, who have won many awards from music instruction magazines. Guitarist John Petrucci has been named as the third player on the G3 tour six times, more than any invited players. In 2009 he was named the No. 2 best metal guitarist by Joel McIver in his book The 100 Greatest Metal Guitarists. He was also named as one of the "Top 10 Fastest Shredders of All Time" by GuitarOne magazine. Jordan Rudess is considered to be one of the greatest keyboard players of all time by many publications like MusicRadar. Former drummer Mike Portnoy has won 26 awards from Modern Drummer magazine and is also the second youngest person (at the age of 37) to be inducted into the Rock Drummer Hall of Fame. His replacement Mike Mangini has also previously set 5 WFD records. John Myung was voted the greatest bassist of all time in a poll conducted by MusicRadar in August through September 2010. The band was inducted into the Long Island Music Hall of Fame in 2010.