If Farber’s antifolates were his first discovery in oncology, then this critical truth was his second. It set off a seismic transformation in his career that would far outstrip his transformation from a pathologist to a leukemia doctor. This second transformation—from a clinician into an advocate for cancer research—reflected the transformation of cancer itself. The emergence of cancer from its basement into the glaring light of publicity would change the trajectory of this story. It is a metamorphosis that lies at the heart of this book.