The emergence of living systems and thus the origin of life are the subject of an independent field of science that is only partly related to evolutionary biology, protobiology. This discipline is faced with two basic question areas. It should tell us how the basic building stones of living organisms were formed, i.e. simple chemical substances of the aminoacid and nucleotide type. These substances are currently formed under terrestrial conditions primarily through the activities of organisms; however, prior to the origin of life, they must necessarily have been formed by some other, abiotic route. Biological evolution must apparently have been preceded by rather complicated chemical evolution, during which the action of various abiotic factors led to the formation and accumulation in the environment of some simple and more complicated organic substances. In the laboratory, it has been possible to copy some of the conditions that could have prevailed on the Earth at the time prior to the origin of life and, under these conditions, scientists have been able to achieve the formation of almost all the important building blocks of present-day biological macromolecules (Fig. X.1).