Statistical Thermodynamics via Computer Simulation to Characterize Phospholipid Interactions in Membranes This chapter describes the major issues that are involved in the statistical thermodynamical treatment of phospholipid membranes at the atomic level. The ingredients going into models of lipid bilayers is summarized: force fields, representation of long-range interactions and boundary conditions, followed by the discussion of the choice of thermodynamic ensembles and the two main options for the generation of a representative sample of configurations: molecular dynamics and Monte Carlo. The final issue that is dealt with describes the various ways the generated ensembles can be analyzed.