The processes leading to the formation of high-dispersed aerosols with particle size below 0.1 μ and the methods of generation and investigation of these aerosols are treated as well as their physical properties differing fundamentally from those of coarse aerosols. In spite of the great role played by high-dispersed aerosols in the important process of vapor condensation in space and their significance for many industries and meteorology, there are no monographs or reviews on this subject available in the literature, and the aim of the present work is to fill this gap.