The deep oceans and global seafloor are truly Earth's last frontier: largely unexplored, yet critical to our survival on this planet. This magnificent, full-color volume provides a unique, fascinating view of Earth's seafloor and underlying oceanic crust, beginning with a historical summary of seafloor exploration and its developing technologies. Later chapters discuss the major geological components of Earth's crust and the myriad environments along the global mid-ocean ridges, including active volcanoes, rift zones and hydrothermal vents - Earth's most extreme environments. The authors present simple explanations of how the various geological and hydrothermal features of the seafloor are formed through physical, chemical and biological processes, and also describe the life they host. Supported by online visual and teaching resources, including video clips and images, this book forms an indispensable reference for researchers, teachers and students of marine geoscience, and a visually stunning resource which all oceanographers and enthusiasts will want on their bookshelves.