The monograph discusses a group of physicochemical phenomena that play a decisive role in disinfection, in particular in the processes of achieving contact between active substances and infectious agents or arthropods. The book is designed for specialists working in the field of disinfection and disinsection. It can be useful as a teaching aid in order to improve the physicochemical training of doctors and biologists. Dispersion Systems, Classification of Dispersion Systems, Stability of Dispersion Systems, Analysis of Variance, Gas Mixtures, Saturated Steam, Gas Density, Solutions, Aerosols, Powders, Suspensions, Emulsions, Methods for Preparing Dispersion Systems, Forms of Disinfection Preparations, Excipients for Preparing Preparations, Physicochemical Features of Treated Surfaces, Role of Physicochemical Factors in Surface Treatment, Role of Physicochemical Factors in destruction of the pathogen or carrier of infection in the air, Physical and chemical control of disinfection.