The maritime industry is thousands of years old. The shipping industry, which includes both ships and ports, follows practices that are as old as the industry itself, yet relies on decades-old information technologies to protect its assets. Computers have only existed for the last 60 years and computer networks for 40. Today, we find an industry with rich tradition, colliding with new types of threats, vulnerabilities, and exposures. This book explores cybersecurity aspects of the maritime transportation sector and the threat landscape that seeks to do it harm.