The Subtle Knot fastens the study of early modern literature to the history of neuroscience in an excellent and timely book that will be of interest to those navigating the sometimes-fraught borders between the humanities and sciences. For Habinek, the predisciplinarity of the early modern period, a moment when neuroscientific inquiry was as much the prerogative of poets as anatomists, challenges C. P. Snow's nearly sixty-year-old injunction of two, separate cultures of the humanities and sciences. She shows how contemporary neuroscience relies on literary metaphors, many of which originated with early modern writers and printers, including John Donne, William Shakespeare, William Harvey, Margaret Cavendish, Thomas Willis, and Joseph Moxon. Transhistorical in its claims yet deeply situated in its evidence, The Subtle Knot attests to a modern disciplinary present bound to a predisciplinary past by metaphor.

In the wake of embodied, distributed, and grounded models of cognition, and with the rise of scholarship in cognitive literary studies by the likes of John Sutton, Evelyn Tribble, and Laurie Johnson, who were primed, of course, by the pathbreaking writing of Mary Crane, the book charts an early modern metaphorics of the brain. The organ was then, as it is now to an extent, a figure of unknowability, particularly to early modern thinkers who sought to understand the uncertain interface of the body and soul. One of Habinek's most convincing arguments is that the emerging field of neuroscience relied on “metaphors shared by other intellectual domains, and, as importantly, that these metaphors were used in those other domains to describe the soul” (38). From these, she specifies five for the brain: the knot (or net), cut (or lesion), womb, machine, and book. To each, she dedicates a chapter.

The Subtle Knot borrows its title from Donne's “The Ecstasy,” a poem that prompts the onto-epistemological conundrum of the first chapter: the locatability of the soul in the rete mirabile, a “wonderful net or miraculous knot” of arteries at the base of the brain where seventeenth-century English anatomists surmised the locus of the rational soul (49). Despite being discredited by Vesalius in the previous century, the rete persisted as an artifact in English sources, even those translated from De Humani Corporis Fabrica. Its endurance bespeaks an anxious desire to fetter the soul to the body, even when, as Habinek points out, its biological existence was more fiction than fact. The second chapter examines the metaphor of the lesion. Regional functions of the brain can be deduced by observing psychomotor deficits caused by damage to neural tissue, a practice Habinek traces back to early modern physicians Franciscus Arceus and Helkiah Crooke, who espoused methods of retrograde diagnosis: from effect to cause. The backward thinking of early modern medicine informs Habinek's reading of Hamlet, wherein she connects the title character's “willed oblivion” to the medical history of treating brain trauma (21).

Subsequent chapters focus on the brain as womb, a gendered metaphor aligning the generative capacities of the imagination with the reproductive functions of the female sex organs. Habinek looks first to Harvey, who appropriates the metaphor to extend his authorial legacy, and then to Cavendish, who upends masculinist tropes of intellectual conception by elaborating the metaphor as a writing machine. The final chapter takes up the pictorial technology of the seventeenth-century flap anatomy to loosen Habinek's final metaphorical knot: the brain as book. She shows how the flapbook's interactive, three-dimensional format translates the experience of the anatomy theater—peeling and folding cadaverous flesh—to print media through illustrated layers that gradually reveal the body's interior. Disentangling the publication histories of Johann Remmelin's Captotrum Miscrosmicus (1613), Thomas Willis's Cerebri Anatome (1664), and An exact survey of the Microcosmus (1670, 1695), she positions the “brain-book” as an instrument for “reading” the soul (203).

The Subtle Knot beautifully weaves multiple strands of neuroscience's literary history, but its conceptual frame glosses over a growing body of neuroscientific research on metaphor and neuroimaging. For instance, her suggestion that CAT and PET scans “force an eerie (if not ghostly) confrontation” proves compelling but ultimately lacks development (204). Nonetheless, her insistence on disciplinary humility, especially from the sciences, strengthens a larger project of showing how “anterior ways of understanding the brain” continue to matter today (22).