Efraim Halevy directed the Mossad, Israel's foreign intelligence service, from 1998 to 2002 and served as national security advisor to Prime Minister Ariel Sharon in 2002-2003.  He now heads the Center for Strategic and Policy Studies at the Hebrew University of Jerusalem, and is the author of Man in the Shadows: Inside the Middle East Crisis with a Man who Led the Mossad (St. Martin's Press).