Justin Steward Furstenfeld (born December 14, 1975 in Houston, Texas) is a record producer, artist, and the lead singer, guitarist, lyricist and frontman of the American rock band Blue October. He played in the band Last Wish until 1995 and uses the moniker 5591 when performing solo. 5591 was Justin's patient number during his stay on a psychiatric ward after he was deeply affected by a relationship break-up.

Read more about 5591 on Last.fm.