  Particle number fluctuations and correlations in nucleus-nucleus collisions
at SPS and RHIC energies are studied within microscopic transport approaches.
In this review we focus on the Hadron-String-Dynamics (HSD) and
Ultra-relativistic-Quantum-Molecular-Dynamics (UrQMD) models The obtained
results are compared with the available experimental data as well as with the
statistical models and the model of independent sources. In particular the role
of the experimental centrality selection and acceptance is discussed in detail
for a variety of experimental fluctuations and correlation observables with the
aim to extract information on the critical point in the $(T,\mu_B)$ plane of
strongly interacting matter.
