Maritime infrastructures are fundamental to the working of societies and economies. They play a crucial role in supply, with 90% of commercial trade exchanges carried out worldwide handled by the maritime industry, in the functioning of the economy, the maintenance of mobility and the deployment of renewable energies. For the past decade, the attention of developed democratic nations has been focused on the protection of vital terrestrial objects, but less attention has been paid to critical maritime infrastructures and the need to increase their resilience. This book, Modern Technologies Enabling Innovative Methods for Maritime Monitoring and Strengthening Resilience in Maritime Critical Infrastructures, presents 23 papers delivered at the NATO Advanced Training Course (ATC) hosted in hybrid format from 15-20 January 2024 in Agadir, Morocco. The aim of the ATC was to cover the problem of monitoring critical maritime infrastructure in an interdisciplinary manner, and it was attended by researchers and students, security officers, stakeholders, and experts in tackling terrorism or other violent threats. The ATC was divided into 4 blocks: general aspects of strengthening the resilience of maritime critical infrastructure; unmanned systems (USs) and sensor network technology; monitoring, data analysis and structural modeling; and cybersecurity and protection of IT maritime infrastructures. There was also one practical session. The book covers many ways in which unmanned systems, sensor networks and other digital technologies can be used to monitor threats to maritime critical infrastructure, and will be of interest to all those working in the field.