"The discovery of cells--and the reframing of the human body as a cellular ecosystem--announced the birth of a new kind of medicine based on the therapeutic manipulations of cells. A hip fracture, a cardiac arrest, Alzheimer's, dementia, AIDS, pneumonia, lung cancer, kidney failure, arthritis, COVID--all could be viewed as the results of cells, or systems of cells, functioning abnormally. And all could be perceived as loci of cellular therapies. In...