The book outlines the theory of molecular structure and chemical bonding. The quantum-mechanical theory of hydrogen-like and multi-electron atoms is briefly considered. In the presentation of the quantum-mechanical theory of chemical bonding and the structure of molecules, the method of molecular orbitals was used. Electronic structure and properties of diatomic and simple inorganic molecules, coordination and aromatic compounds and polyenes, as well as intermolecular interaction are described in mutual connection.