Harry V. Jaffa (October 7, 1918 – January 10, 2015) was Professor Emeritus at Claremont McKenna College and Claremont Graduate University and a distinguished fellow of the Claremont Institute. He has written on Aristotle, Thomas Aquinas, Abraham Lincoln, Thomas Jefferson, Winston Churchill, Leo Strauss, American constitutionalism, and natural law. His most famous work, "Crisis of the House Divided: An Interpretation of the Issues in the Lincoln-Douglas Debates", written in 1959, has been described as "the greatest Lincoln book ever."