Max Cooper, Georgia Research Alliance Eminent Scholar, Professor of Pathology and Laboratory Medicine, Emory University School of Medicine, delivered the 2021 Lasker~APSA Lecture at the annual meeting of the AAP/ASCI/APSA on April 8. Cooper spoke about his research on the evolution of the adaptive immune system. Cooper together with Jacques Miller received the 2019 Albert Lasker Basic Medical Research Award for their discovery of the two distinct classes of lymphocytes, B and T cells – a monumental achievement that provided the organizing principle of the adaptive immune system and launched the course of modern immunology.