Recent years have seen numerous books about the looming threat posed to Western society by biological and chemical terrorism, by narcoterrorists, and by the unpredictable leaders of rogue nations. Some of these works have been alarmist. Some have been sensible and measured. But none has been by Loch Johnson. Johnson, author of the acclaimed Secret Agencies and "an experienced overseer of intelligence" ( Foreign Affairs ), here examines the present state and future challenges of...