Having enjoyed the author�s LATE ROMAN ARMY, I was pleasantly surprised to discover this volume on a recent visit to Rome. Of course any author benefits when writing about the likes of Diocletian, Septimus Severus and Constantine the Great. Southern�s highly readable text, buttressed with extensive illuminating notes and a sound examination of the sources, brings the period alive. I find Southern�s writing to be clear and understandable ---very well-crafted. I found the author�s well-developed bibliography particularly helpful. Passable maps, interesting illustrations and the obligatory, colossal head of Constantine accompany the text as well as a number of numismatological sketches of the era�s coinage. Chester Starr in his brief but excellent THE ROMAN EMPIRE delineates this time period as �The First Test� ---a massive turning point for the empire. Southern does a masterful job examining the evolving threats to the empire including themes such as depopulation, barbarization, succession, usurpation. I also liked her analysis of the mobile, multiethnic war bands of the era as well as her defense of the Emperor Gallienus (not too surprising as she co-authored THE ROMAN CAVALRY). I thoroughly enjoyed this work, in all three readings. I recommend following this up with Birley�s SEVERUS and William�s DIOCLETIAN. The old standby, AMMIANUS MARCELLINUS, is still available in an affordable Penguin abridgment.