Intelligence activities have always been an integral part of statecraft, and the Romans could not have built and protected their empire without them. In both the Republic and the Empire the Romans realized that to keep their borders safe, to control their population, to keep abreast of political developments abroad, and for the internal security of their own regime, they needed a means to collect the intelligence which enabled them to make informed decisions. The Romans certainly did not have our technology nor did they use our terminology. A search for the Roman equivalent of the CIA is fruitless; there was no such thing. But this is not to say that they did not collect intelligence. While no one department of government was ever trusted with all of Rome's clandestine activities, there were several organizations that shared the responsibility of telling the emperor what he wanted to know. Onto their vast system of roads was grafted an intelligence network which carried information from all ends of the empire to the emperor. The men responsible for monitoring that system became, in effect, a Roman Secret Service. What are referred to as intelligence activities, in fact, include a whole range of subjects that are only loosely bound by the fact that modern intelligence services practice those arts. Professor Sheldon uses the modern concept of the intelligence cycle to trace intelligence activities whether they were done by private citizens, the government, or the military. The range of activities is broad: intelligence and counterintelligence gathering, covert action, clandestine operations, the use of codes and ciphers, and many other types of espionage tradecraft have all left their traces in the ancient sources. This book will certainly dispel the myth that such activities are a modern invention. These ancient spy stories have modern echoes as well. We still debate many of the questions that faced the Romans. What is the role of an intelligence service in a free republic? When do the security needs of the state outweigh the rights of the citizen? And if we cannot trust our own security services, how safe can we be? Although protected by the Praetorian Guard, seventy-five percent of Roman emperors died by assassination or under attack by pretenders to his throne. Who was guarding the guardians? In the wake of the World Trade Center attack on September 11th, the world once again has been reminded of how painful and expensive intelligence failures can be. The Romans, too, suffered such disasters, and Sheldon details how the Romans could be tricked, ambushed and even defeated by an enemy with better intelligence on the ground. This is the first work in English , written for the general public, to bring together all of Rome's intelligence activities from the Republic to the high Empire. It is not difficult to see why espionage is often referred to as the World's Second Oldest Profession.