This chapter considers the recent evolution of maritime traffic analysis and monitoring, and presents different cooperative and non-cooperative vessel detection and tracking techniques. It further focuses on data fusion and trajectory processing, and also shows how patterns can be mined from maritime traffic databases. The maritime environment has a huge impact on the world economy and people's everyday lives. Different ship tracking systems have been designed to ensure the security and safety of maritime navigation. These tracking systems can be divided into two general categories: cooperative and non-cooperative. Cooperative systems rely on vessels to identify themselves and report their positions, and include automated identification system (AIS), long-range identification and tracking (LRIT), and vessel monitoring systems (VMS). Non-cooperative systems are designed to detect and track vessels that do not voluntarily provide information about their location.