In post COVID-19 Pandemic, the global geopolitics will be completely different and national security will become more complex. Addressing such issues along with safeguarding national interests remains a major challenge for any country or nation. Book focuses on contemporary security challenges and highlights the internal and external aspects of national security, changing nature of conflict, emerging trends, complex geo-political and security environment. This is the first book ever, which contributed by distinguished Service Chiefs from the Armed Forces, Constitutional Expert, a Governor of the State and a Defence Minister of India on various national and global security issues shared in the General B.C Joshi memorial Lectures series which includes maritime security, geo-strategic concerns of Indo-Pacific, Indian Ocean Region, proxy war, insurgency, threats to critical infrastructure, the role of Indian Air Force in security matrix and Indigenous Science and Technology. This book provides a comprehensive understanding of the national security issues, geo-political compulsions, changing environment of regional security, India’s maritime and security interests. The book reflects the role of armed forces, academia and military in national security and in national development. This book also gives a larger perspective of non-traditional security issues by focusing on the issues of drug trafficking, illegal immigration, fake currency; human trafficking and issue of climate change and argues ignoring such issues has serious implications on national security. Finally, this book enriches the ideas of India’s geo-strategic position; geo-strategic compulsions and security threats, which are significant for determining the foreign and security policies. It is a must-read book in defence and security professionals, strategists, scholars, researchers and security and foreign policy analysts.