It is with great sadness that we learn of the passing of our colleague, mentor and friend. Ken Arrow passed away earlier today, February 21, 2017. For many of us, Ken was the embodiment of our field. We are reminded of his foundational influence on a daily basis in our research and teaching, and through the contributions of the many brilliant scholars he trained. We remember him not only as a legendary intellect, but also as a man of grace and humility who inspired universal admiration and affection. Ken's presence around the department will always be felt and will be greatly missed.