The many-particle system plasma can be described in thermodynamic equilibrium using the well-established methods of equilibrium statistics and thermodynamics. In this respect, the calculations in this chapter are “merely” an application of the principles developed in the corresponding course lectures. However, even in the classical case, the evaluations themselves are by no means trivial; on the contrary: in systems with internal interactions, one quickly encounters very significant mathematical difficulties, the resolution of which remains the subject of intensive research to this day. Quantum statistics are not addressed in this chapter. They are, however, of particular importance in the context of complex plasmas.