The Mental Anatomies of William Godwin and Mary Shelley focuses on the influence of enlightenment and Romantic-era theories of the mind on the writings of Godwin and Shelley and examines the ways in which these writers use their fiction to explore such psychological phenomenon as ruling passions, madness, the therapeutic value of confessions (both spoken and written) and the significance of dreams. In many cases, associationist psychology and the theory of the ruling passions enable Godwin and Shelley to provide fascinating and sophisticated insights into their characters' mental processes and behaviors. A number of their mental anatomies reflect the influence of Jean-Jacques Rousseau's Confessions and his conceptions of mental transparency, sincerity, and environmental conditioning. Because his primary focus is on Godwinian and Shelleyan perspectives on the mind and its operations, Brewer avoids twentieth-century psychological terminology and ideas in his discussions of their fiction.
In The Mental Anatomies of William Godwin and Mary Shelley, Brewer contends that Godwin's and Shelley's literary mental anatomies should be regarded as exploratory and often inclusive thought-experiments. He organizes it by themes rather than by chronology or works. Unlike most studies of Godwin and Shelley, this book does not privilege their masterworks (Caleb Williams and Frankenstein, respectively). For the most part, it focuses on their lesser-known writings. In an effort to contextualize their fictional treatments of fictional themes, Brewer also considers the works of other Romantic-era writers including Mary Wollstonecraft, Joanna Baillie, Mary Hays, Percy Bysshe Shelley, Lord Byron, and Charles Brockden Brown, as well as the seventeenth- and eighteenth-century philosophical and medical theories that informed Godwin's and Shelley's presentations of mental states and types of behavior.
As Brewer points out, Godwin and Shelley sometimes differ in their attitudes towards psychological phenomena. Godwin's horror of insanity contrasts with Shelley's more positive assessment of madness, which she links to the poetic imagination, martyrdom, and extreme forms of altruism. Moreover, whereas Godwin's St. Leon and Fleetwood emphasize the danger of reveries, which can promote asocial behavior and delusional thinking, some of Shelley's works suggest that reveries can be extremely therapeutic for women who need consolation or an outlet for their emotions. These writers share, however, the belief that through analyzing their fictional mental anatomies the reader can gain a better understanding of his or her own psyche and of the human mind in general.