This book comprises the journey of the Indian nation state and its tryst with destiny, where successive political leaderships, while governing India, contributed to a better understanding of the idea of India, its political and strategic culture, and the role that its military has had to play to develop that culture. Hence, the journey has been from the backwaters of 'defensive defence' to create a credible deterrence capacity as well as a doctrine to implement the same through political will and enter the domain of global involvement in the strategic, non-strategic as well as non-traditional areas of security. Thus, the title of the book The Purpose of India's Security Strategy: Defence, Deterrence and Global Involvement. It is hoped that this book will serve as a referral document to understand the polemics of the development of a strategic culture in India for an era which will be dominated by the information age and artificial intelligence, without forgetting that the Indian political leadership has come of age to understand the role of the military in the process of nation building.