Mismapping the Underworld investigates the place of error in the moral and aesthetic system of Dante's Comedy. It argues that Dante's delight in finely wrought patterns does not exclude an interest in patterns of disorder, that his pursuit of harmony intensifies his interest in dissonance.

The three central chapters of the book each examine a different type of error or anomaly: a mismeasured giant, a self-defeating experiment, an erring citation of Virgil. These apparently trivial discrepancies are linked, the author suggests, to much larger questions. What is the status of mimetic realism in Dante's poem? By what right does a poet pretend to represent the order of God's mind? Where does aggressive allegoresis cross over into interpretive error?

Through the study of error, the author offers an alternative account of Dante's poetic project, one that gives priority to wit and self-irony rather than didactic seriousness.

In the author's words, "If there is a moral to this study, it is that instead of suppressing anomalies, cruxes, and contradictions, we might as well learn to enjoy them." In the pursuit of this enjoyment, we encounter analyses of such topics as science and the role of experimentation in the comedy monsters and medieval aesthetics, numerology, and the Renaissance tradition of mapping Hell.

In addition to analyzing Dante's enthusiasm for error, the author also investigates the reluctance of Dante scholars to admit its existence. This discussion, which draws upon some of the more fantastic efforts of six centuries of scholarship, clarifies the critical motives and preoccupations that have shaped the history of the Comedy's reception.