Protecting information, identifying undercover agents, and operating clandestinely--efforts known as counterintelligence--are the primary objectives of terrorist groups evading detection by intelligence and law enforcement officials. Some strategies work well, some fail, and those tasked with tracking these groups are deeply invested in the difference.

Discussing the challenges terrorist groups face as they multiply and plot international attacks, while at the same time providing a framework for decoding the strengths and weaknesses of their counterintelligence, Blake W. Mobley provides...