Book excerpt: The third volume of the fully revised and expanded general catalogue of Roman coins extends coverage of the Imperial series from the accession of Maximinus I in AD 235 down to the assassination of Carinus and the accession of Diocletian half a century later. This turbulent period, during which the Empire came close to total collapse and disintegration, witnessed great changes in the Imperial coinage including unprecedented debasement and the beginning of the decentralization of the mint system.