  VNI is a general-purpose Monte-Carlo event-generator, which includes the
simulation of lepton-lepton, lepton-hadron, lepton-nucleus, hadron-hadron,
hadron-nucleus, and nucleus-nucleus collisions. On the basis of
renormalization-group improved parton description and quantum-kinetic theory,
it uses the real-time evolution of parton cascades in conjunction with a
self-consistent hadronization scheme that is governed by the dynamics itself.
The causal evolution from a specific initial state (determined by the colliding
beam particles) is followed by the time-development of the phase-space
densities of partons, pre-hadronic parton clusters, and final-state hadrons, in
position-space, momentum-space and color-space. The parton-evolution is
described in terms of a space-time generalization of the familiar
momentum-space description of multipl (semi) hard interactions in QCD,
involving 2 -> 2 parton collisions, 2 -> 1 parton fusion processes, and 1 -> 2
radiation processes. The formation of color-singlet pre-hadronic clusters and
their decays into hadrons, on the other hand, is treated by using a spatial
criterion motivated by confinement and a non-perturbative model for
hadronization. This article gives a brief review of the physics underlying VNI,
which is followed by a detailed description of the program itself. The latter
program description emphasizes easy-to-use pragmatism and explains how to use
the program (including a simple example), annotates input and control
parameters, and discusses output data provided by it.
