It has been an honor for me to write the prefatory article for Volume 4 of the Annual Review of Pathology: Mechanisms of Disease. I decided to describe the first 50 years of my career in research, which started with my entry into medical school. I have tried to outline the numerous scientific mentors who played such an important role in my development as an independent scientific investigator. In general, I have tried to avoid mention in the text of the many, many colleagues who carried out the scientific work, as I would inevitably fail to cite many of them. Rather, I have cited what I think are my most important publications, which identify many of these scientific colleagues. I am now engaged nearly full-time in research and look forward to the next period of research progress.