Michael Greenberger, JD, former principal deputy associate Attorney General at the Justice Department, was involved in planning the TOPOFF I counter-terrorism exercise in May, 2000 which involved simulated terrorist attacks in three cities: Denver, Colorado; Portsmouth, NH; and Lanham, MD. Greenberger, now the director of the Center for the Health and Homeland Security at the University of Maryland, can discuss lessons learned from that exercise and lessons to be watched in upcoming counter-terrorism exercise by the federal government called TOPOFF 2.