Four trips to Pervomaysk: preventive defense at work -- Preventive disease -- Pursuing Marshall's vision with Russia and NATO -- Project Sapphire, the Nunn-Lugar program, and arms control -- Dealing with rising China -- Standing at the brink in North Korea: the counterproliferation imperative -- A false alarm (this time): preventive defense against catastrophic terrorism -- The threat within: shaping a force for the future.