Otherworlds: Fantasy & History in Medieval Literature is one of the latest entrants in a burgeoning subfield of research about the fantastical and the wondrous in the Middle Ages. This topic found the strongest declaration of its potential in Caroline Walker Bynum's 1997 American Historical Association presidential address. Her speech sketched the possibilities of using the affective category of wonder to nuance post-colonial, technological, and legal perspectives on medieval works. One could look to Patricia Clare Ingham's The Medieval New (2105) or Wales and the Medieval Colonial Imagination (2015) to see the legacy of Bynum's arguments about the critical possibilities for this work.

Otherworlds lacks the clarity of these other works in that the intellectual or political stakes of the work are never fully realized. This seems to be partly because Byrne draws on a far different scholarly genealogy for her study. Byrne fashions her work as a much-needed reimagining of Howard Rollin Patch's 1950 The Other World According to Descriptions in Medieval Literature, a ponderous volume that Byrne describes as a "taxonomic exercise" rather than a critical engagement with its material (Byrne, 3). Byrne's book promises that it will move beyond merely observing and cataloguing. To this end, Byrne spends much of the book's introduction making clear the difficult task before a scholar seeking to construct a project about "otherworlds" in a way that faithfully represents a concept that has become distorted because of its familiarity:

The term ["otherworlds"] is certainly a convenient one, and it would be both futile and overzealous to suggest purging it from the scholarly lexicon. However, the terms on which medieval 'otherworlds' are understood need some examination and, perhaps, some adjustment. The fact that the terminology medieval writers appear to have used in speaking of these realms often highlights the relative rather than the absolute, and speaks of multiplicity rather than of a clear binary, suggests that the term "otherworld' could profitably be drained of its absolutizing and dichotomizing associations in general scholarly use (21).

This passage is representative of the strengths and pitfalls of Otherworlds. On one hand, the author makes a convincing case that there needs to be a wholesale reappraisal of something that has for too long been a category of experience that is understood but undertheorized within medieval studies. The geography of "otherworlds" in the English imaginary lacks a guide that addresses the concept in its messy, translocal, and highly allusive form.

On the other hand, the study's ambitions constitute its difficulties. The larger goal of Otherworlds is to read the literary deployment of otherworlds as embedded within specific historical circumstances and able to exert force on real-world conceptions of history:

Rather than focusing on how literary depictions of otherworlds draw upon established historical beliefs, this book suggests that it might be more fruitful to consider how the rhetoric of literary worlds is employed in an historical context. Taking this approach illustrates the imaginative impact of depictions of such realms and stresses the degree to which the depiction could impact on the actual world rather than constitute an escape from it (23).

The value of this project and its reversal of how scholars usually make use of otherworlds are abundantly clear. Nonetheless, Otherworlds does not seem to ever fully escape the impulse towards compilation and away from critique. For example, early in Otherworlds' first chapter the author considers what she calls "pseudo-mimesis": a term she coins to refer to the detailed descriptions of otherworlds that imitate reality but ultimately only serve to more firmly fix the reader within the realm of fantasy. To demonstrate her point, the author moves from a brief allusion to Chaucer's Sir Thopas to Marie de France's Lanval to Middle English versions of the same text to the Irish Immram Brain, back through versions of Lanval to Sir Gawain and the Green Knight to Sir Orfeo to Amadas et Ydoineand finally into the Hiberno-EnglishThe Land of Cokaygne, all over the course of eleven pages. The rapidity of the author's transitions and the breadth of her source material can easily leave a reader breathless. The author peels away what appears to be merely trope to reveal the deep connections between far-flung texts. This work demands a high-level of erudition which is on display throughout the book as the writer shifts between languages and cultural contexts to draw sources together. This is nowhere more evident than in the work the author does to insist on the place of Irish texts next to English ones that have enjoyed far more critical attention.

Byrne concedes that her task is a daunting one given the amount of material she seeks to cover in this slender volume. The rewards of this book are like one of the trips to an otherworld Byrne describes. Readers get a glimpse into a vast field of texts full of surprises, however what you can take with you is only fleeting. The study's great value is its ability to change one's perspective on what has come to seem mundane in the landscape of medieval literature.