Thermalization and isotropization in heavy-ion collisions

I review our current understanding of the processes driving the thermalization and isotropization of the quark gluon plasma (QGP) created in ultrarelativistic heavy ion collisions (URHICs). I begin by discussing the phenomenological evidence in favor of the creation of a thermal but momentum-space anisotropic QGP in URHICs. I then discuss the degree of isotropization using viscous (dissipative) hydrodynamics, weak-coupling approaches to QGP dynamics, and strong-coupling approaches to QGP dynamics. Finally, I report on recent progress in the area of real-time non-abelian gauge field simulations and non-abelian Boltzmann-Vlasov-based hard-loop simulations.