Risk can be thought of as the product of consequence times probability. No one can assign a number to the probability, for example, that a terrorist gang will acquire a nuclear weapon, although experts think the probability is considerably greater today than at any previous time. We do know, however, that the consequences of a nuclear explosion in any major population center would be catastrophic. The inescapable conclusion is that the global community is facing a very serious risk. What I want to discuss with you today is what is being done to deal with it and what still needs to be done.