We have long recognized in the Iliad the hallmarks of the oral, traditional poet who chooses among alternative arrangements of formulaic elements. In The Power of Thetis, Laura M. Slatkin makes us aware of another compositional resource, just as crucial to our understanding of the meaning of Homeric epic. Slatkin shows how, through the selection and combination of mythic motifs, Homer interprets mythological traditions and locates his characters within them by allusion or oblique reference. The figure of Thetis, the mother of Achilles, provides an especially revealing example of the way in which such mythological resonance contributes a wider context and meaning to the epic's central themes. Slatkin teaches us to listen for what is unspoken as well as spoken in the poetry of Homer, and thereby confronts us with the larger questions of the function of epic and its boundaries as a genre.