This text aims to familiarize the reader with the principles and terminology of reliability engineering which has become a subject of great importance. It looks at methods for improving reliability and the approaches of deterministic and statistical reliability engineering are explained in such a way that the practical implications of the equations become clear. Methods of handling the reliability of large and complex systems are discussed, and a chapter is devoted to software reliability. Problems with full solutions are provided. The book is intended for advanced undergraduate and postgraduate students of mechanical, production, aero and electrical/electronic engineering.