Problem of correctness, i.e. the problem of verification that a given computer (hardware and/or software) system has the properties required by its specification, belongs to the fundamental problems of practical and theoretical computer science. The continuing development of information technologies leads to constructing systems with increasing complexity, and thus both research and industrial practice need solidly based verification procedures. Automated verification, comprising also so called `model checking', was established as a class of methods successfully applied in practice during the 1990s. In model checking, the property to be tested is expressed, e.g., in a simple temporal logic, and is verified by (semi)automatic methods on a system model. The aim of the course is to explain the basic principles of this (automated) verification, and to demonstrate them on models of concrete practical problems, for which suitable freely available software verification products exist.