  An introductory review to short-time critical dynamics is given. From the
scaling relation valid already in the early stage of the evolution of a system
at or near the critical point, one derives power law behaviour for various
quantities. By a numerical simulation of the system one can measure the
critical exponents and, by searching for the best power law behaviour, one can
determine the critical point. Critical slowing down as well as finite size
corrections are nearly absent, since the correlation length is still small for
times far before equilibrium is reached. By measuring the (pseudo) critical
points it is also possible to distinguish (weak) first-order from second-order
phase transitions.
