About the AuthorVinay Kumar, MBBS, MD, FRCPath, Donald N. Pritzker Professor and Chairman, Department of Pathology, Biologic Sciences Division and Pritzker School of Medicine, The University of Chicago, Chicago, Illinois; Abul K. Abbas, MBBS, Distinguished Professor and Chair, Department of Pathology, University of California San Francisco, San Francisco, California Jon C. Aster, MD, PhD, Professor of Pathology, Harvard Medical School; Brigham and Womens Hospital, Boston, Massachusetts