Treating the cosmological constant as a thermodynamic pressure and its conjugate quantity as thermodynamic volume, we reconsider the critical behavior of AdS black holes. We complete the analogy between the thermodynamics of charged AdS black holes and that of the liquid/gas system. The corresponding critical point occurs at a point of divergence of specific heat at constant pressure and is characterized by critical exponents that coincide with those of the Van der Waals fluid. For more complicated black holes, phenomena like reentrant phase transitions, triple points, and even that of the isolated critical points are observed.