A young molecular biologist at the forefront of HIV research, Nathalia Holt tells the historic, multilayered, and compassionate story of two patients--each known in medical literature as the Berlin Patient--and their young research-minded doctors. The backdrop is nothing less than a revolution in cultural attitudes and medical thinking. These two patients' disparate cures came twelve years apart: the first in 1996 from an experimental cancer drug, the other in 2008 from a bone marrow transplant of cells with a particular genetic mutation. Holt connects the molecular dots of these two cases for the first time, providing insight into one of the most important medical breakthroughs of our generation.