Book excerpt: The interplay between Geology and Biology has shaped the Earth from the early Precambrian, 4 billion years ago. Moving beyond the borders of the classical core disciplines, Geobiology strives to identify chains of cause-and-effect and synergisms between the geo- and the biospheres that have been driving the evolution of life in modern and ancient environments. Combining modern methods, geobiological information can be extracted not only from visible remains of organisms, but also from organic molecules, rock fabrics, minerals, isotopes and other tracers. An understanding of these processes and their signatures reveals enormous applied potentials with respect to issues of environment protection, public health, energy and resource management. The Encyclopedia of Geobiology has been designed to act as a key reference for students, researchers, teachers, and the informed public and to provide basic, but comprehensible knowledge on this rapidly expanding discipline that sits at the interface between modern geo- and biosciences.