Exploratio investigates how intelligence was gathered and handled in the Roman Empire, in the long term to help formulate strategy and in the short term for tactical reasons. Austin and Rankov discuss who gathered it and for whom, and how it grew in sophistication and accuracy over the six centuries from the outbreak of the Second Punic War in 218 BC to the Battle of Adrianople in AD 378.

The authors show how proper archives and communications contributed towards improving readiness against threats to the Empire's external security, and lessening the serious effects that mistakes and shortcomings could have on battles and campaigns. The book also demonstrates how information was collected and processed by various bodies in the military and administrative spheres, and how it made a considerable impact on policy formation at all levels - from the purely local to the global.