Book excerpt: In Ancient Science and Dreams, M. Andrew Holowchak analyzes the ancient notion of science of dreams throughout Greco-Roman antiquity, from the Classical Greece in the fifth century B.C. to the Roman Republic in the fourth century A.D. Holowchak investigates psycho-physiological accounts, interpretation of prophetic dreams, and the use of dreams in secular and non-secular medicine. Culling from some of the fullest and most important accounts of dreams and ordering the presentation in each section chronologically, the author analyzes the extent to which empirical and non-empirical factors guided ancient accounts in Greco-Roman antiquity.