This book presents new and updated developments in the molecular theory of mixtures and solutions. It is based on the theory of Kirkwood and Buff which was published more than fifty years ago. This theory has been dormant for almost two decades. It has recently become a very powerful and general tool to analyze, study and understand any type of mixtures from the molecular, or the microscopic point of view. The traditional approach to mixture has been, for many years, based on the study of excess thermodynamic quantities. This provides a kind of global information on the system. The new approach provides information on the local properties of the same system. Thus, the new approach supplements and enriches our information on mixtures and solutions.

There are essentially two theories of solutions that can be considered exact: the McMillan-Mayer theory and Fluctuation Solution Theory (FST). The first is mostly limited to solutes at low concentrations, while FST has no such issue. It is an exact theory that can be applied to any stable solution regardless of the number of components and their co

This book was planned and written with one central goal in mind: to demonstrate that statistical thermodynamics can be used successfully by a broad group of scientists, ranging from chemists through biochemists to biologists, who are not and do not intend to become specialists in statistical thermodynamics. The book is addressed mainly to gradu ate students and research scientists interested in designing experiments the results of which may be interpreted at the molecular level, or in interpreting such experimental results. It is not addressed to those who intend to practice statistical thermodynamics per se. With this goal in mind, I have expended a great deal of effort to make the book clear, readable, and, I hope, enjoyable. This does not necessarily mean that the book as a whole is easy to read. The first four chapters are very detailed. The last four become progressively more difficult to read, for several reasons. First, presuming that the reader has already acquired familiarity with the methods and arguments presented in the first part, I felt that similar arguments could be skipped later on, leaving the details to be filled in by the reader. Second, the systems themselves become progressively more com plicated as we proceed toward the last chapter.

An overview of classical solutions and their consequences in quantum field theory, high energy physics and cosmology for graduates and researchers.