The goal of exobiology is to increase knowledge of the origin, evolution, and distribution of life in the universe. This is a multidisciplinary science, and the conceptual and experimental tools of virtually all scientific disciplines and branches of learning are relevant. In seeking answers to such questions as how the development of the solar system and its planets led to the origin of life on Earth, how planetary evolution subsequently influenced the course of biological evolution, and where else life may be found in the solar system and beyond, exobiology brings together life scientists and physical scientists in a common interest. The scope of those perceptions has expanded beyond the reaches of the solar system to the stars and the interstellar clouds that populate the seemingly limitless expanse of space. We see life as the product of countless changes in the form of primordial stellar matter wrought by the processes of astrophysical, planetary, and biological evolution. The science of exobiology attempts to reconstruct the natural history of processes and events involved in the transformations of the biogenic elements from their origins in nucleosyntheses to their participation in Darwinian evolution in the solar system on planet Earth. From this reconstruction will emerge a general theory for the evolution of living systems from inanimate matter.