  The search for the critical point of QCD in heavy-ion collision experiments
has sparked enormous interest with the completion of phase I of the RHIC beam
energy scan. Here, I review the basics of the thermodynamics of the QCD phase
transition and its implications for experimental multiplicity fluctuations in
heavy-ion collisions. Several sources of noncritical fluctuations impact the
observables and need to be understood in addition to the critical phenomena.
Recent progress has been made in dynamical modeling of critical fluctuations,
which ultimately is indispensable to understand potential signals of the QCD
critical point in heavy-ion collision.
