Awareness on National Security is vital part of whole UPSC Civil Services Examination. Based on the past experiences, the topic of National Security starts from - Preliminary Examination in the form of objective questions on various defense equipment's or military exercises. - In Main Examination, around 4 questions (50 Marks) of General Studies-III are directly related to the topics covered under National Security. - Finally, in the Interview Stage, at least one interview board member is more likely to ask questions related to internal and external security of India, if not more. So, based on these needs of the examination and past experiences, our book 'National Security Strategy: Securing India Internally and Externally' carries five broad chapters with some other sections to develop a holistic understanding on the internal and external security environment of India. Help is taken from not just the recent National Security perspectives but also from our past with the works of Kautilya (Chanakya) and wise advice's from Mahabharata and other Sages. All of that is condensed to impart information on not just the topics of Civil Service Examination topics, i.e.- Linkages between development and spread of extremism; Role of external state and non-state actors in creating challenges to internal security; Challenges to internal security through communication networks, role of media and social networking sites in internal security challenges, basics of cyber security; money-laundering and its prevention; Security challenges and their management in border areas - linkages of organized crime with terrorism; and Various Security forces and agencies and their mandate But to give detailed perspectives on the war, national security strategy and future challenges to be faced by India, so that you can develop your own understanding on the whole topic of National Security and answer questions based on greater insights. We would suggest our readers to first have a basic reading of the book and later, segregate the topics for various stages of Civil Services Examination based on the Syllabus given at the start of book and previous year Main Examination questions given at the end of book. The Chapter list of the book is a follows: CHAPTER 1 - Understanding National Security CHAPTER 2 - Conflict, Negotiations and War CHAPTER 3 - Our Leadership Structure & Mandate of Executive Agencies CHAPTER 4 - Challenges to Internal Security of India & Solutions CHAPTER 5 - Challenges to External Security of India & Solutions This book can also be used by avid security learners and aspirants preparing for other competitive examinations like CAPF, CDS, NDA etc.