  In addition to its importance in describing high-energy processes themselves,
the dynamics of multiparticle production is part of the general field of
non-linear phenomena and complex systems. Multiparticle dynamics is one of the
rare fields of physics where higher-order correlations are directly accessible
in their full multi-dimensional characteristics under well-controlled
experimental conditions. Multiparticle dynamics, therefore, is an ideal testing
ground for the development of advanced statistical methods. Higher-order
correlations have, indeed, been observed as particle-density fluctuations.
Approximate scaling with finer resolution provides evidence for a self-similar
correlation effect. Quantum-Chromodynamics branching is a good candidate for a
dynamical explanation of these correlations in e+e- collisions at CERN/LEP and,
as expected, also of those in pp collisions at future CERN/LHC energies.
However, other sources such as identical-particle Bose-Einstein interference
effects also contribute. A particular question at the moment is the smooth
transition from the QCD branching domain (gluon interference before
hadronization) to the Bose-Einstein domain (identical-pion interference after
hadronization). Both mechanisms have clearly been observed in e+e- collisions
at CERN/LEP energies. The large amount of high-resolution data being collected
at LEP will allow the study of the genuine (i.e. non-trivial) higher-order
correlations in both domains.
