This is the first detailed analysis of the fate of Lucretius' De rerum natura from its composition in the 50s BC to the creation of our earliest extant manuscripts during the Carolingian Age. Close investigation of the knowledge of Lucretius' poem among writers throughout the Roman and medieval world allows fresh insight into the work's readership and reception, and a clear assessment of the indirect tradition's value for editing the poem. The first extended analysis of the 170+ subject headings (capitula) that intersperse the text reveals the close engagement of its Roman readers. A fresh inspection and assignation of marginal hands in the poem's most important manuscript (the Oblongus) provides new evidence about the work of Carolingian correctors and offers the basis for a new Lucretian stemma codicum. Further clarification of the interrelationship of Lucretius' Renaissance manuscripts gives additional evidence of the poem's reception and circulation in fifteenth-century Italy.

Book IV of Lucretius' great philosophical poem deals mainly with the psychology of sensation and thought. The heart of this book is a new text, incorporating the latest scholarship on the text of Lucretius, with a clear prose facing translation. The commentary concentrates on the thought of the text (relating it to other philosophers beside Epicurus) and the poetry of the Latin, placing the text in relation to Roman literature in general, and attempting to demonstrate the poetic genius of Lucretius. The introduction deals with the didactic tradition in ancient literature and Lucretius' place in it, the structure of De Rerum Natura, the salient features of the philosophy of Epicurus and the transmission of the text.