In 1910, Lev Tolstoy died of pneumonia in a filthy house at a provincial train station. He had fled home at the urging of his closest disciple, Vladimir Chertkov, a cunning, talentless man. How did the ­mediocre Chertkov come to be beside Russia’s greatest writer as he died, even as Tolstoy’s wife, Sophia, stared through the window, denied entry? In “Tolstoy’s False Disciple,” Alexandra Popoff, the author of the biography “Sophia Tolstoy” and “The Wives: The Women Behind Russia’s Literary Giants,” draws on long unavailable archival materials, including Chertkov’s letters, to examine the relationship that tore apart Tolstoy’s family and threatened his literary legacy.

The wealthy, spoiled Chertkov met Tolstoy, 26 years his senior, because of their shared interest in a Christianity that rejected the Orthodox Church. Chertkov, who didn’t care for literature, convinced Tolstoy that they were soul mates by simply parroting his philosophy. By then, Tolstoy was lost in the thicket of his own ideals, torn between what he believed and what he desired. He seems to have felt there was something holy in submission to Chertkov’s will, but the bond wasn’t strictly spiritual. Chertkov liked to keep plenty of handsome peasant youths ­nearby; as a young man, Tolstoy had written that he’d loved only men, and never women. He worried, pathetically, about Chertkov not loving him enough, even as friends and family wondered how such a great man could love such a cad.

Soon Chertkov was reading Tolstoy’s diary — a privilege reserved, until then, for Sophia. He was allowed to edit Tolstoy’s work and his papers, sometimes making large cuts and even rewriting sections, including sections of his diaries. He urged Tolstoy to focus on religious writing, and to revise his fiction to make it more didactic. Where major works were concerned, Tolstoy’s literary instincts rebelled, and he rejected Chertkov’s meddling. But most of the time, he submitted meekly. He accepted Chertkov’s writing assignments and revised Chertkov’s poorly written articles. He allowed Chertkov to send him on errands — to hire a wet nurse, to scout real estate, to buy asparagus. (Chertkov complained when the asparagus was ­wilted; Tolstoy went back to the merchant and returned with a fresh box.) Chertkov kept blank sheets with Tolstoy’s signature and wrote letters on his behalf, though his bad Russian betrayed him. He had Tolstoy sign a document stating that he and his wife were Tolstoy’s closest friends. Caring only about money and speed, the spendthrift Chertkov hired hack translators and tried to publish Tolstoy’s unfinished drafts. He pressed Tolstoy to send him rough descriptions of plot ideas, apparently believing that he could cash in on them after Tolstoy’s death. Most important, he persuaded Tolstoy to make him his literary executor.

Chertkov’s motives may have gone beyond greed, obsession or love of fame. Under the pretext of making a compendium of the writer’s thoughts, Chertkov had his scribes copy Tolstoy’s papers, including his diaries. Some of the scribes were also spies, reporting to Chertkov on Tolstoy’s activities. Chertkov became Tolstoy’s private censor, pressing him to tone down his criticisms of the government. He stored his large archive of Tolstoy’s papers — including parts of Tolstoy’s private diary — at the house of a general who was notorious for police brutality, and who had close ties to the secret police. Popoff’s research suggests that Chertkov may have been an agent of the government, which, afraid of Tolstoy’s subversive ideas, kept the writer under surveillance for the last 50 years of his life.