1. The text matter has been revised and recast wherever a need was felt to make the treatment more systematic and easier for the student to understand and learn.
2. To facilitate smooth study, Hints to Selected Questions have been given at the end of the exercises.
3. Chapter Summary and Chapter Test have been given at the end of every chapter. It is hoped, that will help the students in revising, consolidating and evaluating their understanding of the concepts learnt in the chapter.