Classical stellar evolution theories have undergone some drastic changes in recent decades. New insights into the development of stellar interiors were obtained from studying stars in various stages of thei lives, as well as with the help of fast computers, which gave the boost to the branch of numerical modelling of stellar structure and evolution. This book is divided into two parts. The first part deals with the general aspects of stellar structure and evolution including information on numerical modelling. The second part deals with specific evolutionary aspects of single and binary stars with a variety of masses. The last chapter gives several models of stars with specific masses. The text is intended as an introduction to students as well as a reference to researchers.