my fellows and residents. They have missed their teacher quite a bit during the "hot" periods of this project, and they paid me back, not by compla- ing, but by asking pertinent questions and by providing me with interesting cases. I would like to thank Peter Jaksch and Walter Klepetko from the Lung Transplantation Unit of my home University of Vienna, Austria. Their clinical and surgical competence, combined with their reliability, have made our daily collaboration a productive and enjoyable partnership. I owe my deep gratitude to Pierre Alain Gevenois, Department of Radiology, and Marc Estenne, Lung Transplantation Unit, both at the Hôpital Erasme, University of Brussels, B- gium. Their support, expertise, and friendship have aided our fruitful research collaboration in the ? eld of lung transplantation over the past decade. Without their ongoing input, many things would simply not have happened. I would also like to thank Christiane Knoop, Alain Van Muylem, and Denis Tack, all from the same institution, for satisfying my often intrusive (and most likely annoying) avidity for their help and knowledge. It is to Ursula N. Davis at Springer-Verlag that I sincerely apologize for my sometimes more than undulating working rhythm, a rhythm she tolerated with admirable patience and humor. Without her moral support and her enduring determination, I would not have made it through this project. I am also grateful to Prof. Albert L.