He has authored more than 400 professional publications and 50 books, including Psychology and Life, The Lucifer Effect: Understanding How Good People Turn Evil and The Time Paradox.Media Contact: Shirley Skeel, sskeel@pugetsound.edu Gettysburg College, Gettysburg, Pa.David Gergen will deliver the keynote on May 19 at Beachem Portico, north side of Pennsylvania Hall, Gettysburg College campu