Door Number Three is a clever, well-written, and intricately constructed debut novel. Despite spinning variations on many classic science-fiction themes, it is boldly original. It betrays few evidences of being a first novel, as O’Leary worked with editor David Hartwell for seven years to hone the novel through multiple drafts. Its prose is smooth and polished, its characters vivid and memorable, and its plot gripping.

O’Leary manages to juggle time travelers, alien abductions, government conspiracies, and dream-eating monsters without ever descending into clichés. He slowly and skillfully invests the Holock with a sense of menace far more frightening than the standard “alien grays” so often depicted in popular media. While the novel’s themes of paranoia and loss of reality have earned O’Leary comparisons with Philip K. Dick, the analogy distorts as much as it reveals. While Dick’s best work displays an organic paranoia that reflects the disorder in his hapless protagonists’ minds, O’Leary’s carefully crafted plot forces these experiences on his protagonist from without.

The intricate twists and turns deployed in the time travel portions of Door Number Three recall the equally ingenious plotting of Robert A. Heinlein’s “By His Bootstraps.” While the idea of “mental” time travel has been used before, the idea of changes in the future rippling back to effect the past may be original to O’Leary. The ambitious looping and nesting structure of the novel as a whole merits comparison with K. W. Jeter’s The Glass Hammer (1985) and Geoff Ryman’s The Child Garden (1989). As in those overlooked masterpieces, the story itself could not be told in a linear narrative with the same impact.

Door Number Three ranks alongside Mary Doria Russell’s The Sparrow (1996), Ken MacLeod’s The Star Fraction (1995), and Raphael Carter’s The Fortunate Fall (1996) as one of the most impressive science fiction debuts of the 1990’s. O’Leary afterward went on to publish The Gift (1997), a flawed but engrossing fantasy, and Other Voices, Other Doors: A Collection of Stories, Meditations and Poems (2000). O’Leary may yet prove to be one of science fiction’s major talents.