This book is designed to provide a comprehensive introduction to the economic theories, both the established and the less orthodox, behind some of the most vital areas of economics today. The topics covered include welfare economics, international trade, income and employment, trade cycles and economic growth, public finance and economic systems. Each topic is clearly elucidated with different theories and models lucidly explained with the help of diagrams and graphs. For each chapter there are exercises and multiple choice questions. The author, a professor of economics, is the author of many books and numerous research articles on economic theory.