Illegal, Unreported and Unregulated (IUU) fishing is widely recognised as a transdisciplinary problem requiring holistic action at international, regional and national level. IUU fishing implicates many different areas, including fisheries and oceans sustainability, safety at sea, working conditions on board fishing vessels, food security and livelihoods, human rights violations, and fisheries crime. These problems are particularly acute in developing countries, which often lack the monitoring, control and surveillance (MCS) capacity to cover the large ocean areas under their control. The CAPFISH Project aims to address this problem through education of maritime and oceans professionals on the forefront of the fight against IUU fishing in developing countries. This includes the creation of educational materials, which are made freely available in an effort to improve understanding of the problem and tools available to address it. This book serves as one such publication and features contributions from presenters at two educational workshops offered by the Project in October 2021 and February 2022. Contributions cover the benefits of implementing international instruments set up to tackle IUU fishing; case studies from Navies, Coast Guards, and other practitioners; socioeconomic and security issues related to IUU fishing; transparency and tracking of fishing vessels; and the need for cooperation and coordination to address IUU fishing.