It is with no small measure of sadness that we reflect on the life of Professor J. Michael Bishop, who passed away in March at age 90. Mike was a towering figure in biomedical science whose scientific leadership and discoveries had enormous and lasting impact on the University of California, San Francisco (UCSF)—his home institution for over 50 years—and on the biomedical sciences nationally and internationally. Indeed, Mike and Harold Varmus’ 1976 co-discovery of the cellular origins of the avian retroviral oncogene v-Src reshaped our understanding of the genetic underpinnings of cancer and led to safe and effective treatment strategies for numerous human malignancies.