Exploration, Military and Political Intelligence in the Roman World from the Second Punic War to the Battle of Adrianople, by N.J.E. Austin and N.B. Rankov, Routledge, New York, 1995, $62.95.
Drawing on new information derived from archaeology and inscriptions, Exploratio is the first comprehensive study of military intelligence as gathered and used by the Roman legions
The official Roman staff was the concilium or officium, which consisted of legati (“legates”), delegated subordinate commanders; exploratores (“scouts”); and beneficiarii (“beneficiaries”), native clients of the commander, from whom he got information on the local strategic and tactical situation. The official staff also included a haruspex–an entrail-examiner or omen-reader.
In addition to describing fascinating details on the gathering and use of intelligence, as well as other aspects of legionary life, the book follows the changes of Roman high command–diffused under the Republic, unified in the early Empire, chaotic in the third century, and finally, from 286 ad on, a joint or dual authority in the form of the Eastern and Western emperors.