The book deals with Growth Theory, one of the most interesting as well as important subjects universities across the world teach at the Master's level. It is based on lectures delivered to Master's level students and Research Scholars at the Indian Statistical Institute, the Jawaharlal Nehru University, the Delhi School of Economics, the Indian Institute of Technology, Kharagpur, Kobe University, Japan, and the City University of Hong Kong. In order to take into account student inputs, several batches of students were exposed to the ideas presented here, who provided their feedbacks to the author. The book provides an in depth treatment of Old Growth Theory and then follows it up with the best known works in New Growth Theory. In addition, to ensure that the book serves the purpose of a classroom textbook, the exercises have been added at the end of each chapter that teachers can use to test the understanding of the students. The first two chapters deal with Control Theory which is explained in detail with reference to the best known of Growth Theory Models, viz. Robert Solow's neoclassical model of growth. These ideas extend easily to the later chapters as well. The first two chapters of the book can be used for a first year Master's level course in Macroeconomics as well, though the book as a whole deals with the subject of Economic Growth, which is usually taught as a special paper at the second year Master's level. Finally, given that the book starts off with numerical examples relating to the Indian economy, it should appeal to students studying in Indian universities.