This introductory chapter provides an overview of the book"s contents and definitions of key concepts including benthic habitat, potential habitat, and seafloor geomorphology. The chapter concludes with a summary of commonly used habitat mapping technologies. Benthic (seafloor) habitats are physically distinct areas of seabed that are associated with particular species, communities, or assemblages that consistently occur together. Benthic habitat maps are spatial representations of physically distinct areas of seabed that are associated with particular groups of plants and animals. Habitat maps can illustrate the nature, distribution, and extent of distinct physical environments present and importantly they can predict the distribution of the associated species and communities. The data sets collected for constructing habitat maps provide fundamental information that can be used for a range of management and industry applications, including the management of fisheries, spatial marine environmental management, design of marine reserves, supporting offshore oil and gas infrastructure development, port and shipping channel construction, maintenance dredging, tourism, and seabed aggregate mining. Seafloor habitat mapping provides fundamental baseline information for decision-makers working in these sectors. GeoHab (www.geohab.org) is an international association of marine scientists conducting research using a range of mapping technologies into the use of biophysical (i.e., geologic and oceanographic) indicators of benthic habitats and ecosystems as proxies for biological communities and species diversity. Using this approach, combinations of physical attributes of the seabed identify habitats that have been demonstrated to be effective as surrogates for the benthic communities that they typically support. Thus management priorities can be identified using seabed habitat maps as a guide. The work of GeoHab demonstrates how knowledge of seabed properties can be employed to guide marine environmental management, marine resource management, and conservation efforts. Seafloor geomorphology is one of the more useful of the physical attributes of the seabed mapped and measured by GeoHab scientists. Different geomorphic features (e.g., submarine canyons, seamounts, atolls, fjords, etc.) are commonly associated with particular suites of habitats. Knowledge of the geomorphology and biogeography of the seafloor has improved markedly over the past 15 years. Using multibeam sonar, submarine features such as fjords, sand banks, coral reefs, seamounts, canyons, and spreading ridges have been revealed in unprecedented detail. The case studies presented in this book represent a range of seabed geomorphic features where detailed bathymetric maps have been combined with seabed video and sampling to yield an integrated picture of the benthic communities that are associated with different types of benthic habitat.