In both 1910 and 2010, The Carnegie Foundation for the Advancement of Teaching used existing educational innovations and learning theory to point the way to the future of medical education. Flexner's transformative report of 1910 was strongly influenced by the innovative curriculum at Johns Hopkins University School of Medicine and by educational principles of the Progressive Era. In 1912, Flexner wrote a similar critique of medical education in Europe. These two reports have powerfully shaped medical education for the past century. Yet much has changed since then, which prompted The Carnegie Foundation for the Advancement of Teaching to commission another report that was published in 2010. Drawing on contemporary educational innovations and research from the learning sciences, the authors make four recommendations for reform: (1) standardize on learning outcomes while individualizing the learning process, (2) integrate formal knowledge with clinical experience, (3) imbue habits of inquiry and improvement to achieve lifelong learning and excellence, and (4) explicitly cultivate the formation of professional identity. In this article, the author describes educational innovations and educational principles relevant to each of these four recommendations.