From pirates to smugglers, migrants to hackers, from stolen fish to smuggled drugs, the sea is becoming a place of increasing importance on the global agenda as criminals use it as a theatre to conduct their crimes unfettered. This volume sets out to provide an introduction to the key issues of pertinence in Maritime Security today. It demonstrates why the sea is a space of great strategic importance, and how threats to security at sea have a real impact for people around the world. It examines an array of challenges and threats to security playing out at sea, including illegal, unreported and unregulated fishing, irregular migration, piracy, smuggling of illicit goods, and cyber security, while also looking at some of the mechanism and role-players involved in addressing these perils. Each chapter provides an overview of the issue it discusses and provides a brief case study to illustrate how this issue is playing out in real-life. This book thus allows readers an insight into this evolving multidisciplinary field of study. As such, it makes for an informative read for academics and practitioners alike, as well as policymakers and students, offering a well-rounded introduction of the main issues in current Maritime Security.