Christopher Chyba is a professor of astrophysics and international affairs at Princeton University, and past director of the Program on Science and Global Security. As an associate professor at Stanford University before coming to Princeton, he co-directed the Center for International Security and Cooperation and held the Sagan Chair at the SETI Institute. He has been a Marshall Scholar and a MacArthur Fellow. During President Clinton’s first term, he served on the national security staff at the White House, entering as a White House Fellow. He served as a member of President Obama’s Council of Advisors on Science and Technology (PCAST) from August 2009 through January 2017, on which he co-chaired the Biodefense Working Group.