We are living in precarious times at present and India, especially, is facing multiple and formidable security challenges. These include threats, such as Hinterland Terrorism, Militancy in Jammu and Kashmir, Insurgency in the North-East, Left-Wing Extremism and Riots and Mob Violence. In that perspective, Internal Security becomes an important topic in UPSC Mains GS 3 Syllabus. This book is a detailed compendium of Internal Security and Disaster Management. The book throws light on how organized crime and money laundering are not only security challenges in themselves but are also intricately connected to terrorism and other forms of extremism. It further delves onto the threats emanating from the cyber domain and social media that have emerged as another major security concern in the country. Further, the security issues along the border areas - land border, maritime waters and airspace - cannot be delinked to the internal security challenges and has been detailed with updated data and sources in the book.