The question, where does life on Earth come from, was answered by T. and R. Chamberlin as early as in 1908 with the speculation that reactive organic compounds delivered by meteorites and other “ambassadors” of the space were delivered to the early Earth and stimulated a chemical evolution (Chamberlin and Chamberlin 1908). In the year 1961, the American chemist J. Oro published a detailed description and discussion of the influence, extraterrestrial chemicals and forces might have had on the chemical processes on Earth (Oro 1961). According to his view, comets were the predominant vehicles that brought biochemicals to the early Earth and initiated a chemical evolution, which resulted in formation of the first cells. It was the same chemist who succeeded with the first model synthesis of a nucleobase (adenine) under quasi prebiotic conditions (s. Sect. 5.2 ). In the following decades, the hypothesis that the CE on Earth was initiated by “space chemicals” found more and more followers. Any kind of particles raining down from space was suspected to be effective carriers. In addition to comets, meteorites, micrometeorites, and interstellar dust particles were taken into account (Chyba and Sagan 1992; Ehrenfreund 1997; Jesenberger 1999; Pierazzo and Chyba 1999; Glavin et al. 2011; Burton et al. 2012).