Principles of Physical Chemistry, Second Edition uniquely uses simple physical models as well as rigorous treatments for understanding molecular and supramolecular systems and processes. In this way the presentation assists students in developing an intuitive understanding of the subjects as well as skill in quantitative manipulations. The unifying nature of physical chemistry is emphasized in the book by its organization - beginning with atoms and molecules, and proceeding to molecular assemblies of increasing complexity, ending with the emergence of matter that carries information, i.e. the origin of life, a physicochemical process of unique importance. The aim is to show the broad scope and coherence of physical chemistry.