Division and separation are the dominant themes of Boyle's dark-hued and deftly plotted seventh novel, which bears strong incidental resemblances to his earlier World's End (1987) and The Road to Wellville (1993), though it displays a richer Dickensian brio throughout. The title denotes a California mansion built on the spot where a growing acorn had split open a boulder, thence attaining full maturity. Which is more than can be said for Stanley McCormick, who might be called this novel's agonist. He's the youngest son of millionaire Chicago inventor Cyrus McCormick; a ``neurasthenic'' young man driven by a chaos of terrifying formative experiences into a state of sexual dementia so uncontrollable that he must be restrained in ``a world without women,'' under the watchful eye of a physician who studies the social habits of lower primates. Stanley's doctors come and go, over the years, but despite unpredictable intervals of lucidity he remains locked away and guarded, most faithfully by his ``head nurse'' Eddie O'Kane, a likable roustabout who has his own problems with compulsive behavior, and women. We follow the story of Stanley's long incarceration, beginning in 1912, through Eddie's sometimes glazed- over eyes. In parallel narratives, Boyle entwines with it the dispiriting tale of Stanley's haunted youth and deranged manhood, and also the story as lived by his wife Katherine Dexter McCormick, a strong-willed and accomplished beauty, still a virgin decades after her wedding day, who has sublimated her unfulfilled love for her husband among what Eddie angrily dismisses as ``birth control fanatics and blood-sucking feminists.'' The issues that divide the emergent century and the gulf that separates the sexes thus frame, and memorably echo, this big novel's narrative and emotional core: the craziest love story imaginable, but a love story nevertheless- -one that chills the bones as you read. Vintage Boyle: a freakishly inventive black comedy, populated with irresistible eccentrics, that leaves a bracing and bitter aftertaste.