Greek literature is divided, like many literatures, into poetry and prose; but in the earlier Roman Empire, 31 BC to AD 300, much Greek (and Latin) prose was written in one organized rhythmic system. Whether most, or hardly any, Greek prose adopted this patterning has been entirely unclear; this book for the first time adequately establishes an answer. It then seeks to get deeper into the nature of prose-rhythm through one of the greatest Imperial works, Plutarch’s Lives. All its phrases, almost 100,000, have been scanned rhythmically. Prose-rhythm is revealed as a means of expression, which draws attention to words and word-groups. (Online readings are offered too.) Some passages in the Lives pack rhythms together more closely than others; the book looks especially at rhythmically dense passages. These do not occur randomly; they attract attention to themselves, and are marked out as climactic in the narrative, or as in other ways of highlighted significance. Comparison emerges as crucial to the Lives on many levels. Much of the book closely discusses particular dense moments, in commentary form, to show how much rhythm contributes to understanding, and is to be integrated with other sorts of criticism. These remarkable passages make apparent the greatness of Plutarch as a prose-writer: a side not greatly considered amid the huge resurgence of work on him. The book also analyses closely rhythmic and unrhythmic passages from three Greek novelists. Rhythm illuminates both a supreme Greek writer, Plutarch, and three prolific centuries of Greek literary history.