The EU-coordination action Deep-Sea and Sub-Seafloor Frontier, DS3F, develops strategies for sub-seafloor sampling to contribute to a better understanding of deep-sea and sub-seafloor processes by connecting marine research in life and geosciences, climate and environmental change, as well as socio-economic issues and policy building. DS3F tries to establish a long-lived research approach that considers (i) the need for a sustainable management of the ocean, and particularly the deep sea with enhanced activity (fishery, hydrocarbon exploration, deep-sea mining), (ii) the necessity to unravel deep-seated geological processes that drive seafloor ecosystems, and (iii) the value of seabed archives for the reconstruction of paleo-environmental conditions and the improved prediction of future climate change. Sub-seafloor drilling and sampling can provide two key components in understanding how deep-sea ecosystems function at present, and how they will respond to global change: (a) an inventory of present subsurface processes and biospheres, and their links to surface ecosystems, including seafloor observation and baseline studies, and (b) a high resolution archive of past variations in environmental conditions and biodiversity. For both components, an international effort is needed to share knowledge, methods and technologies, including mission-specific platforms to increase the efficiency, coverage and accuracy of sub-seafloor sampling and exploration. The basis for the DS3F White Paper resulting from the coordination action is multi-disciplinary research in all areas of the deep-sea, i.e. geosphere-biosphere interaction, deep biosphere, geofluids and gas hydrates, sediment dynamics and geohazards, climate change, ecosystem functioning, and the technologies and infrastructures to foster such research. The book will present some exemplary research results in these fields, each manuscript with previously unpublished data and with an outlook chapter on the repercussions of the results for the next decade(s) of deep sea research.