Yasiin Bey, formerly known as Mos Def, is an American rapper and actor. A prominent figure in conscious hip hop, he is recognized for his use of wordplay and commentary on social and political issues, such as police brutality, American exceptionalism, and the social status of African Americans.
He launched his hip hop recording career in 1994 and joined his siblings in the short-lived rap group Urban Thermo Dynamics, and guest appeared on albums by Da Bush Babees and De La Soul. In 1996, he and fellow Brooklyn-based rapper Talib Kweli formed the duo Black Star, whose debut album Mos Def & Talib Kweli Are Black Star contained the singles "Definition" and "Respiration". He released his solo debut, Black on Both Sides, in 1999, which was followed by The New Danger, True Magic, and The Ecstatic. His 2000 single "Oh No" remains his sole entry on the Billboard Hot 100 as a solo act. In 2014, About.com listed him 14th on its "50 Greatest Rappers of All Time".