The main types of organic reactions are considered depending on the nature of reagents and substrates. Mechanisms and conditions affecting the course of reactions are described in detail. The basic concepts of organic chemistry (chemical reaction; homogeneous and heterogeneous reactions, etc.), the influence of various parameters on the rate of a chemical reaction (temperature, pressure) is explained, as well as some theories, equations and principles are presented, with the help of which they describe the phenomena observed during chemical processes.