  Microcanonical statistics can be well applied to non-extensive systems like
nuclei, atomic clusters and systems at phase transitions of first order with
inhomogeneous configurations like phase separation. No thermodynamic limit has
to be invoked. It allows to determine the transition temperature, latent heat
and surface entropy. In the present paper this is demonstrated for systems of
200 - 3000 Na-, K-, and Fe-atoms at 1 atmosphere. As the energy is an exactly
conserved quantity it is a usefull control parameter to tune through the
development of the transition from the liquid side of the coexistence region
over the evaporation, multifragmentation towards the final gas side.
Microcanonical thermodynamics thus resolves details of the mechanism leading to
the phase transition.
