The Greeks, in Dr. Johnson’s phrase, ‘shock the mind by ascribing effects to non-entity’. The culture of ancient Greece was thronged with personifications. In poetry and the visual arts, personified figures of what might seem abstractions claim our attention. This study examines the logic, the psychology and the practice of Greeks who worshipped these personifications with temples and sacrifices, and addressed them with hymns and prayers. Emma Stafford conducts case-studies of deified ‘abstractions’, such as Peitho (Persuasion), Eirene (Peace) and Hygieia (Health). She also considers general questions of Greek psychology, such as why so many of these figures were female. Modern scholars have asked, Did the Greeks believe their own myths? This study contributes importantly to the debate, by exploring widespread and creative popular theology in the historical period.