He granted me the freedom to pursue all my ideas. His support and suggestions were very valuable. I am also grateful for the financial support by the Deutsche Forschungsgemeinschaft during the three years I was working on this thesis. Many thanks to Matthew Bate and Ralf Klessen for providing the SPH code, and for their help and useful discussions. Thanks to Bill Herbst and Andy Nelson for the thorough reading of the manuscript.
Astrophysics is an area in which sense is one of the most important issues.
But in order to keep mental balance, it is crucial that one does not lose contact to nonsense. Thanks to Steffi and Thorsten for accompanying me during this therapy. Thanks to my wife Cordula, who helped me to stand up and go on whenever I stumbled, and for her extraordinary patience.