Professor William Cohen passed away on April 11, 2015. Author of an influential series of articles on national rights to equal citizenship under the Fourteenth Amendment and other aspects of federalism, William Cohen has devoted over 50 years to the study and teaching of constitutional law. In addition to his scholarship in the field of federal jurisdiction, Professor Cohen is the editor of a major constitutional law casebook, which is currently in its 12th edition, and a longtime teacher of torts. He has been a visiting professor at Arizona State University College of Law, where he served as the Merriam Distinguished Visiting Professor. Before joining the Stanford Law School faculty in 1970, he was a professor of law at the University of California at Los Angeles School of Law and at the University of Minnesota Law School. Early in his career he clerked for Justice William O. Douglas of the U.S. Supreme Court.