The seventh edition of this highly successful textbook analyzes the history, evolution, and processes of national security policies. It examines national security from two fundamental fault lines - the end of the Cold War and the evolution of contemporary terrorism dating from the 9/11 terrorist attacks - and traces their path up to ISIS and beyond. The book considers how the resulting era of globalization and geopolitics guides policy. Placing these trends in conceptual and historical context and following them through military, semimilitary, and nonmilitary concerns, National Security treats its subject as a nuanced and subtle phenomenon that encompasses everything from the global to the individual with the nation at its core. New to the Seventh Edition An assessment of the impact of the Trump presidency on national security and relevant domestic policies, including border security and energy security matters. The continuing impact and evolution of terrorism as a security problem, with notable emphasis on the decline of the Islamic State (IS) and what terrorist threats are likely to succeed it. A description of the cyber security problem with an emphasis on Russian efforts to interfere with the 2016 US presidential election and beyond. A revised delineation of the geographic and substantive challenges facing the United States in the form of a chapter on "lethal landscapes," emphasizing the rise of China as a global rival and opponent in Asia and an attempt to deal with state aspirants like the Kurds. This book will continue to be highly beneficial to students and scholars working and studying in security studies, military and strategic studies, defense studies, foreign policy, US politics and international relations.