Despite many advances, human biology is still largely a black box. It is true that decades of intense study have given researchers a detailed understanding of particular characteristics—the phenotypes—of cells and tissues that have been altered by disease. And in recent years, dramatic progress in gene sequencing has made it possible for scientists to make correlations between these phenotypes and specific genes. But the complex network of interactions lying between the two is largely unknown. This is the realm of biomedical data science, the use of quantitative methods and large datasets to trace basic physiological processes.