This is the first monograph devoted to investigation of the most complex physical processes - phase transitions, critical phenomena and super-molecular organization - of soft systems, including a wide class of solutions from associated to micellar ones. Their thermophysical parameters are determined, and special attention is paid to problems of emergence and stability of the microemulsion state. The monograph also blends modern theoretical understanding and experimental results, while new methods and models for the description of several soft systems are proposed. The book is intended for scientists, engineers, graduate and doctoral students interested in the problems of the physics of soft matter.