The book "Basic Principles of Cosmetology" is aimed at students of the Department of Aesthetics and Cosmetology at the Technological Educational Institute of Athens, aestheticians, pharmacists, chemists, dermatologists, and every professional involved in the production, distribution, and application of cosmetic products. The content of the book consists of nine chapters, which refer to the basic properties of surfactants (hydrocarbons and organosilicons), dispersion systems, rheology, the stability of emulsions, the preservation of cosmetic products, as well as the production of preservatives-free cosmetics, oxidation and common antioxidants, colors, basic principles of cosmetic production, and some elements of cosmetic legislation.