  I review Klaus Kinder-Geiger's contributions to the physics of relativistic
heavy ion collisions, in particular, the Parton Cascade Model. Klaus developed
this model in order to provide a QCD-based description of nucleus-nucleus
reactions at high energies such as they will soon become available at the
Brookhaven Relativistic Heavy Ion Collider. The PCM describes the collision
dynamics within the early and dense phase of the reaction in terms of the
relativistic, probabilistic transport of perturbative excitations (partons) of
the QCD vacuum. I will present an overview of the current state of the
numerical implementations of this model, as well as its predictions for nuclear
collisions at RHIC and LHC.
