Many, if not most, processes of interest occur in solutions. It is therefore somewhat
unfortunate that our understanding of solutions and their properties remains rather
limited. There are essentially two theories of solutions that can be considered
exact. These are the McMillan–Mayer theory of solutions and Fluctuation Solution
Theory (FST), or the Kirkwood–Buff (KB) theory of solutions. The former has
practical issues, which limit most applications to solutes at low concentrations.
The latter has no such issues. Nevertheless, the general acceptance and apprecia￾tion of FST remains limited. It is the intention of this book to outline and promote
the considerable advantages of using FST/KB theory to study a wide range of solu￾tion properties