Comet nuclei are the most primitive bodies in the solar system. They have been created far away from the early Sun and it is supposed that their material has been altered the least since their formation. The workshop was bringing together representatives of several scientific communities in the fields of interstellar clouds, star-forming regions, the solar nebula, and comets. The intent was to formulate the current understanding and interconnectivity of the various source regions of comet nuclei and their associated compositions and orbital characteristics. The goal was to better understand the survival of cometary materials (grains, molecules, free radicals, and atoms) from extrasolar sources (circumstellar shells and molecular clouds), their modifications in the solar nebula, and the effects of their properties on the formation and early physical and thermal evolution of the macroscopic bodies, the comet nuclei, in the various subnebulae. Closely associated is their transport into the outer solar system, the Kuiper belt and Oort cloud. The distinction between direct measurements, in situ or by remote sensing, of cometary material properties and properties derived from indirect means, deduced from laboratory studies and theoretical deductions, was emphasized with the aim to guide future investigations. The book is intended to serve as guide for researchers and graduate students working in the field of planetology and solar system exploration. It should also help to influence the planning of scientific strategies for the encounter of the Rosetta spacecraft with Comet Churyumov-Gerasimenko.