From the atomic bomb in 1945 to gene therapy, Francisco Barriga takes us through the fascinating history of the milestones that have shaped what we now know as bone marrow transplantation. It is a story led by giants of medicine—many of whom the author knew personally—who advanced the field by unraveling highly complex biology, often misunderstood by their contemporaries. But this book is not only a history of medicine: woven into the narrative are the real stories of families who faced their children's cancer and for whom transplantation became a second chance at life. These are stories filled with anguish, sorrow, determination, and joy when the outcome was positive—often against all odds. The author also shares reflections from nearly forty years of medical practice and conveys the profound emotions found in his relationships with children and their families, revealing a deeply human and compassionate side of medical work.