The book is written to meet the requirements of B.A., B.Sc., students. The subject matter is exhaustive and attempts are made to present things in an easy to understand style. In solving the questions, care has been taken to explain each step so that student can follow the subject matter themselves without even consulting others. A large numbers of solved and self practice problems (with hint and answer) have been included in each chapter to make students familiar with the types of questions set in various examinations.