Acknowledging the scientists who blazed intellectual trails before him, Isaac Newton wrote, “If I have seen a little further it was by standing on the shoulders of giants.” In this special annual series, we invite our audience to stand on the shoulders of a modern-day giant. In 2015, we were honored to present an address by a titan of physics, Edward Witten. Professor Witten is a leading light of superstring theory and the only physicist to have won the vaunted Fields Medal, mathematics’ highest honor. Known for advancing a number of novel approaches in mathematics and physics, Witten opened up new vistas in 1995 when he unified five seemingly competing superstring theories into M-theory, which seeks to unify Einstein’s general theory of relativity with quantum mechanics.