Biophysicist James Till and cellular biologist Ernest McCulloch changed the world when they discovered stem cells in the 1960s. Through informative images and an accessible narrative, readers will learn how differences in their upbringings, fields of study, and even personalities helped their groundbreaking work. In this extensive look at the world of stem cells, then and now, students will experience the excitement of the Canadian duo's discovery and the impact it had, as well as learn the intricacies of the scientists' laboratory work and its long-reaching effects.