  We present an introductory review of the early time dynamics of high-energy
heavy-ion collisions and the kinetics of high temperature QCD. The
equilibration mechanisms in the quark-gluon plasma uniquely reflect the
non-abelian and ultra-relativistic character of the many body system. Starting
with a brief expose of the key theoretical and experimental questions, we
provide an overview of the theoretical tools employed in weak coupling studies
of the early time non-equilibrium dynamics. We highlight theoretical progress
in understanding different thermalization mechanisms in weakly coupled
non-abelian plasmas, and discuss their relevance in describing the approach to
local thermal equilibrium during the first ${\rm fm}/c$ of a heavy-ion
collision. Some important connections to the phenomenology of heavy-ion
collisions are also briefly discussed.
