  Non-commutative crepant resolutions are algebraic objects defined by Van den
Bergh to realize an equivalence of derived categories in birational geometry.
They are motivated by tilting theory, the McKay correspondence, and the minimal
model program, and have applications to string theory and representation
theory. In this expository article I situate Van den Bergh's definition within
these contexts and describe some of the current research in the area.
