  We address the gas, liquid, and crystal phase behaviour of active Brownian
particles in three dimensions. The nonequilibrium force balance at coexistence
leads to equality of state functions for which we use power functional
approximations. Motility-induced phase separation starts at a critical point
and quickly becomes metastable against active freezing for P\'eclet numbers
above a nonequilibrium triple point. The mean swim speed acts as a state
variable, similar to the density of depletion agents in colloidal demixing. We
obtain agreement with recent simulation results and correctly predict the
strength of particle number fluctuations in active fluids.
