“Nothing makes sense except in the light of evolution” (Dobzhansky, 1964). Evolutionary (or Darwinian) Medicine is a relatively new field at the intersection of evolution and medicine that uses evolutionary theory and approaches to (i) address questions related to the molecular and physiological mechanisms that underlie health and disease, (ii) understand why we are susceptible to disease, and (iii) explore ways to prevent and treat disease. This course provides (i) an overview of evolutionary theory and principles as they apply to the evolution of multicellularity, development and defense mechanisms, and (ii) a framework to appreciate the role of evolution in health and disease (including cancer, aging, and infectious diseases).