FOR YEARS EDVARD RADZINSKY, THE SOVIET Union's most celebrated living playwright, was a man possessed. He stopped writing plays in 1989. He rarely left his Moscow home, except to haunt various national archives. He could think about only one thing: Czar Nicholas II and the mysteries surrounding his family's bloody demise in the wake of the Bolshevik Revolution of 1917. "It was like an illness," Radzinsky says. "I felt it was my mission to write about it. I was so obsessed that I started calling myself the last victim of the last Russian czar."

Finally, the victim has recovered, thanks to the publication in July of his The Last Tsar: The Life and Death of Nicholas II, an exhaustively researched volume that has so far spent eight weeks on a New York Times best-seller list and will be published in Russia (where such things move more slowly) next year. Radzinsky contradicts the official Soviet version of events, which blamed the Romanovs' execution on a band of wayward rural Bolsheviks; instead, Radzinsky points the finger at Bolshevik leader V.I. Lenin himself. He provides chilling firsthand accounts of the slaughter—told in the winds of the assassins—and raises intriguing new questions about the long-rumored possibility that at least one of the children may have survived. All of this unfolds in 432 fast-paced pages that, as Los Angeles Times reviewer Jay Parini put it, "recall many of the great Russian novels of the 19th century." Says Radzinsky: "I'm surprised by the popularity of my book. I thought only books about Princess Diana would have mass appeal."

Given the force of his own obsession, he should have known better. The son of a Moscow writer and a housewife, Radzinsky, now 54, was first tantalized by the doomed Romanovs at age 16, when he was an undergraduate student at Moscow's Institute of Historical Archives. By night the aging actress from whom he rented rooms would regale him with glamorous tales of prerevolutionary St. Petersburg, while by day Radzinsky was perusing Nicholas II's 50-volume diaries. "I decided I had to find the real man and uncover the mystery of his death," he says.

He also had to make a living and chose playwriting as his métier, establishing himself as a major dramatist even before he graduated from the institute with his third effort, a romance titled 104 Pages About Love. Between plays—he has written 30 to date—he pursued his pet project in Moscow's libraries and archives. "I had heard rumors that there were documents that would give me the truth about the assassination of Nicholas," he says. "But they were classified, and I had no permission to read them." His big breakthrough came in 1979 when a friend at the Central Archive of the October Revolution risked imprisonment and slipped him a set of files containing the testimony of Yakov Yurovsky, the Romanovs' chief executioner on the night of July 17, 1917.

Yurovsky told of herding the czar, his wife, Alexandra, their five children and four retainers, all of whom had been held in a merchant's home in the Ural Mountains since Nicholas's March abdication, into the basement of the house and opening fire. Nicholas and Alexandra died immediately, but the hemophiliac son Alexei along with "his sisters, the lady-in-waiting and Botkin [the family physician] had to be finished off." Yukovsky wrote. "This amazed the commandant since we had aimed straight for the heart. It was also surprising that the bullets from the revolvers bounced oil for some reason and ricocheted, jumping around the room like hail." The family diamonds, it turned out, had been sewn into the children's clothing. After finishing the job with bayonets, the 12 executioners loaded the bodies onto a truck, doused them with sulphuric acid and buried at least some of them in an abandoned mine. (Since the truck was left unattended at one point, Radzinsky concluded that any children still living could theoretically have been spirited off to safety.)

It wasn't until the advent of glasnost that Radzinsky could finally go public with his grim findings. In 1989 he published them, along with a coded telegram he had discovered that informed Lenin the family would be executed according to his earlier instruction, in the Soviet journal Ogonyok. He was immediately deluged with phone calls and letters offering further information. Among the hundreds of people he eventually interviewed was a psychiatrist who in 1948 had treated a hemophiliac who claimed he was Alexei. Radzinsky uncovered no new evidence about Anna Anderson, one of the many women who over the years have claimed to be Anastasia, the youngest of the Romanov daughters. But he began taking both stories seriously alter the discovery last year that nine bodies, not the expected 11, were interred in the Romanovs' grave. In the book, he reserves final judgment. "As a historian I find the possibility that there were survivors too incredible—it's too fairytale, and history is usually boring," he says. "But as a writer, I'm absolutely convinced."

Even with some mysteries still unsolved, the publication of his book has freed Radzinsky from his Romanov fixation. The Last Tsar contains just about everything he wanted to say—thanks in large part to his U. editor. Jacqueline Onassis. "Many people wanted to cut this book, but she believed in it." he says. "I fell she had a deep sympathy for this unhappy family and their fate." Says Onassis, who also edited The Marquis de Custine's Empire of the Czar: "Radzinky's playwright's instinct for motivation enabled him to relentlessly follow clues and uncover astounding new information. His accuracy has been impressive."

Radzinsky has taken to writing plays again, working in the study of the modest three-room apartment he occupies alone. (Though he won't discuss his personal life, he admits he been married and divorced three times and has one child.) But another obsession—a book on Stalin that he promises will be even more-shocking than The Last Tsar—has already taken root in his soul. "The political situation in Russia is unstable," Radzinsky says. "At first after Communism fell, they allowed me access to all documents. Now they are beginning to classify again. Anything can happen.... I believe I will have to hurry."

KIM HUBBARD
TERRY SMITH in Moscow