Mike Waterfield, former director of the Ludwig Institute for Cancer Research at University College London, died on May 11, 2023, at the age of 81. A preternaturally gifted scientist, Mike made seminal discoveries in the early 1980s on the regulation of cell growth and its relationship to cancer, showing—most notably—that the ErbB oncogene is the retroviral counterpart to the epidermal growth factor receptor. Later, as Director of Ludwig’s UCL Branch, he authored an extensive body of research on PI3 kinase and its targeting for the treatment of cancer. Six cancer drugs aimed at the growth-regulating enzyme are today in use around the world. Mike earned his PhD at King’s College and moved to the U.S. in 1967 for his postdoctoral studies, first at Harvard University and then at the California Institute of Technology, where his work contributed to dramatic advancements in protein sequencing technologies. He returned to the U.K. in 1972, recruited to the Imperial Cancer Research Fund Laboratories, which he left in 1986, when he established Ludwig’s UCL Branch. His work on PI3K led to the launch of Ludwig’s first startup company, Piramed, which the drug giant Roche acquired in 2008. That same year, Mike wound down his lab—and an exemplary life of science—to enjoy retirement. He is survived by his wife Sally and daughters, Lucy and Rosie.