This monograph is devoted to the most important of Seneca's tragedies, Thyestes, which has had a notable influence on Western drama from Shakespeare to Antonin Artaud. Thyestes emerges as the mastertext of 'Silver' Latin poetry, and as an original reflection on the nature of theatre comparable to Euripides' Bacchae. The book analyses the complex structure of the play, its main themes, the relationship between Seneca's vibrant style and his obsession with dark issues of revenge and regression. Substantial discussion of other plays - especially Trojan Women, Oedipus and Medea - permits a comprehensive re-evaluation of Seneca's poetics and its pivotal role in post-Virgilian literature. Topics explored include the relationship between Seneca's plays and his theory of the emotions, the connection between poetic inspiration and the Underworld, and Seneca's treatment of time, which, in a perspective informed by psychoanalysis, is seen as a central preoccupation of Senecan tragedy.