Concurrently with Frankenstein Unbound, Aldiss was working on Billion Year Spree (1973), a history of science fiction, which he published the same year as the novel (1973). It opens with a chapter on Mary Shelley and considers Frankenstein to be the first science-fiction novel, the “origin of the species.” Calling Frankenstein “the first great myth of the industrial age,” Aldiss finds that it “foreshadows many of our anxieties about the two-faced triumphs of scientific progress” and “the disintegration of society which follows man’s arrogation of power. We see one perversion of the natural order leading to another. Frankenstein is loaded with a sense of corruption....” Frankenstein Unbound, even more so, has this sense, and it is Mary Shelley’s concepts that Aldiss explores in more depth in his novel.

It is at the same time a gloss on Frankenstein, to which it is also indebted for its structure. Both begin as epistolary narratives and then shift to the first-person narrative of the protagonist. During the course of Frankenstein Unbound, Joe analyzes Mary, her milieu, and the characters, episodes, and ideas of her fiction, and she herself tells him the circumstances under which she began her work, while Victor later summarizes for Joe the experiences of the monster during the period in which he was abandoned and before he killed William.

Up to the point at which Mary has not yet completed the novel—the point at which Victor has promised to make the monster a mate—Aldiss follows the outlines of Mary Shelley’s novel, though he alters the characters in it; thereafter, he feels free to change the course of events, as Bodenland interferes with them. Though Joe complains that his recollections of the novel were obscured by travesties of it on film, Aldiss borrows from the James Whale films Frankenstein (1931) and The Bride of Frankenstein (1935) the title of Baron Frankenstein, the details of Victor’s laboratory in the tower of a ruined castle, and the image of villagers with torches who might come to burn it, though they never do.

Frankenstein Unbound is not only a science-fiction novel but also to some extent a historical novel, as Aldiss re-creates in some critical detail the world of 1816 before he alters it with slips in time and space. In contrasting the world of 2020 with the Romantic era of the early nineteenth century and the developments between them, Aldiss shows considerable historical awareness.

Besides the innumerable film sequels, there are several forgettable novelistic sequels to Frankenstein by inconsequential authors. Aldiss, one of the preeminent British science-fiction writers, has not written a sequel but has entered the novel and created an alternate-universe version of it that enables him to explore in more depth the themes and meanings that Mary Shelley originally raised.