MRS. EINSTEIN By Anna McGrail Norton. 333 pp. $24.95 Reviewed by Jay Parini, a poet and novelist who teaches at Middlebury College. His most recent book is "House of Days," a collection of poems. Imagine a novel that contains the following: "We had worked out that only one form of the metal -- Uranium-235 -- was going to be capable of sustaining a chain reaction. Only the U-235 nuclei were easily split, but they formed only one part in 300 of the metal. The U-238 nuclei, which formed the overwhelming bulk of the uranium, usually just absorbed anything that hit them. That was one of the reasons my calculations had been so awry." This mind-boggling explanation occurs in the center of this astonishing novel by Anna McGrail, an English writer who has published one previous novel. In Mrs. Einstein she takes on the ambitious task of putting the history of modern science, and the discovery of the atomic bomb, at the center of a novel; theories of modern physics become, in effect, a literal and symbolic matrix that holds in place the unfolding story of McGrail's eponymous narrator, Lieserl Einstein. The author has imagined a life obscured by history. Apparently Albert Einstein and his future wife, Mileva Maric, produced a girl called Lieserl in 1902, a year before they were married. They were at the time both students at the Swiss Federal Polytechnic in Zurich. The birth occurred in Mileva's native village in Hungary, and it was quickly hushed up; the girl was given up for adoption. After Einstein and Mileva married, they had two sons (but were divorced in 1918). Lieserl's existence was not uncovered until 1986, and nothing much is known about her. This was fertile ground for the right novelist, and McGrail is she. Her ample knowledge of modern physics, including the race to discover the atomic bomb, is evident here; indeed, she makes the quest for scientific knowledge absorbing as she imagines a course Lieserl's life might have taken, beginning with her restricted childhood on a remote Hungarian farm. In McGrail's story, she is raised by the slightly deaf Desanka, her adoptive "mother," who explains to her that her father is a "Technical Officer in the Berne Patent Office." Lieserl immediately begins to speculate on what this could possibly mean: "I imagined that the Berne Patent Office had turrets," she says. "Battlements. Crenellated towers. A drawbridge, possibly, and a moat." But her fantasies are soon corrected, and she discovers that her father is a scientist, concerned with gravity and light. Instinctively competitive, Lieserl says: "If they {gravity and light} were my father's chosen weapons, I had to know every single thing about them." Somewhat implausibly for an ill-educated country girl, she becomes in her own right a brilliant scientist, intent on beating her father to the punch on his intellectual quest. As Lieserl's obsessive interest in the father who abandoned her grows more intense, she travels to the heart of modern science and the devastating politics of the '30s and '40s. Amidst the devastation that seems to befall her at every turn, she makes "calculations. Long silver threads of them. Measure the rate of this, the speed of that, do it often enough and you could come up with the rules which made things behave in the time-honoured ways." Her demonic goal is to use her scientific discoveries to create a bomb that will dismay Einstein, her pacifist father. To her credit, McGrail manages to suggest that these "time-honored ways" Lieserl alludes to involve not only the flawed science of the pre-modern period but also the corrupt social ideas (especially the patriarchal system) that led to her removal from the bosom of her real family. Lieserl's fanaticism, in the odd calculus of this story, seems eerily justified. Mrs. Einstein describes Lieserl's bizarre, tortuous path toward her larger-than-life father, with whom she ultimately has a deathbed confrontation. Her physical journey takes her from the remote village in Hungary where she was raised to Vienna (brilliantly evoked) during the First World War. Tutored by a charismatic German woman, who becomes a lifelong companion, she marries a Jewish businessman and has two children. After becoming a cutting-edge physicist in Nazi Germany, she experiences the death camps firsthand, then flees (via London) to the United States, where she gets involved in the Manhattan Project. McGrail describes this complex trajectory in remarkably authentic detail, although one has continually to suspend belief almost to the breaking point to imagine that Lieserl Einstein could (given her limited training) have outmatched her genius-father on his great intellectual journey. "In Science," Lieserl comments shrewdly, "the only thing that distinguishes the past from the future is the accumulation of disorder. The more we go on, the more, despite our best efforts, things become disordered." This is certainly true of Lieserl's life, which in Anna McGrail's mythic telling represents all that has gone wrong in this unhappy century.