  The event-by-event analysis of high energy nuclear collisions aims at
revealing the richness of the underlying event structures and provide unique
measures of dynamical fluctuations associated with QGP phase transition. The
major challenge in these studies is to separate the dynamical fluctuations from
the many other sources which contribute to the measured values. We present the
fluctuations in terms of event multiplicity, mean transverse momentum, elliptic
flow, source sizes, particle ratios and net charge distributions. In addition,
we discuss the effect of long range correlations, disoriented chiral
condensates and presence of jets. A brief review of various probes used for
fluctuation studies and available experimental results are presented.
