Mos Def, now professionally known as Yasiin Bey, is an American rapper, songwriter, producer, and actor from New York City. Widely recognized as one of the leading voices in conscious and alternative hip-hop, he is known for blending rap with jazz, soul, funk, and spoken word influences.

Mos Def rose to prominence in the late 1990s with the critically acclaimed collaborative album Mos Def & Talib Kweli Are Black Star (1998), recorded with Talib Kweli. His solo debut, Black on Both Sides (1999), is considered one of the greatest hip-hop albums of its era, featuring standout tracks such as Ms. Fat Booty, Mathematics, and Umi Says. He later released The New Danger (2004), True Magic (2006), and The Ecstatic (2009), all of which showcased his artistic versatility and received widespread critical acclaim. In addition to music, Mos Def has built a successful acting career, appearing in numerous acclaimed films and television productions.

What makes Mos Def unique is his thoughtful lyricism, socially conscious themes, and ability to fuse multiple musical styles into a distinctive artistic vision. His influence on alternative hip-hop has been profound, and he remains one of the most respected and innovative artists in contemporary rap.