This volume, unlike those prior to it, consists of a single monograph covering the timely topic of confined fluids. Volume 24 features the thermodynamics of confined phases, elements of statistical thermodynamics, one-dimensional hard-rod fluids, mean-field theory, treatments of confined fluids with short-range and long-range interactions, and the statistical mechanics of disordered confined fluids. Six appendices are included, which cover the mathematical derivation of equations used throughout the book.