Maps showing the distribution of animal and plant communities on the seabed – known as habitat maps, are essential for the wise marine management of human activities to deliver sustainable development. The Mapping European Seabed Habitats (MESH) project tackled the challenge to produce a comprehensive framework to ensure future mapping work could operate in a consistent, quality assured manner to create maps that are fit for purpose. The MESH Blue Book summarises the key achievements of the MESH project, describing its main outputs and suggesting how they can help the European marine policy initiatives that aim to deliver the 'sustainable use of marine goods and services by present and future generations'.