Homogeneous Nucleation Theory: The Pretransition Theory of Vapor Condensation discusses the influence of classical thermodynamics, statistical mechanics, and multistate kinetics on the homogeneous nucleation theory. This book is organized into 10 chapters and begins with a simple model calculation that yields an important insight into the major physical features governing supersaturated vapor condensation. The following chapters explore the development of the theory of equilibrium thermodynamics pertinent to the study of a nucleation phenomena and a postulatory formulation of statistical mechanics and its relation to the calculation of the thermodynamic potentials. The discussion then shifts to a statistical thermodynamics description of an imperfect gas assuming the droplet model of Band-Bijl-Frenkel and to the development of the multistate kinetics of cluster formation. The book also explores the development of the classical Einstein theory for crystalline solids and generalizes this theory for its applications to planar surfaces of microcrystalline clusters. It also presents a comparison of the exact free energies for the microcrystallites with the predictions of the droplet model using the capillarity approximation. Three distinct approaches for calculating the thermodynamic properties of physical clusters are covered in the concluding chapters.