The aim of the course to introduce the student to computational chemistry as a practical tool to solve chemical problems. As background we will cover the basic principles and applications of modern theory of bonding. The three main themes are: potential energy surfaces, force field methods and quantum methods. Practical and computational aspects will be emphasized. After a review of some basics of molecular structure and modeling and the basic concepts of quantum mechanics, the course outlines in detail the various approximate methods of quantum chemistry avoiding purely mathematical derivations as much as possible. Qualitative aspects of bonding will be emphasized based on molecular orbital theory.Hybridization, aromaticity, ligand field theory and group theory will be discussed. Skills to analyze specific calculations will be developed. Spring.