By Alex Goldfarb with Marina Litvinenko

Free Press. 369 pp. $27

nolead ends nolead begins The Litvinenko File
nolead ends nolead begins By Martin Sixsmith

St. Martin's Press. 312 pp. $24.95

nolead ends British Prime Minister Gordon Brown makes his first visit today to President Bush. Eavesdrop through your own surveillance program and you'll doubtless hear the name Alexander Litvinenko.

First the facts about this spectacular case of pinpoint nuclear murder.

Litvinenko, born in Russia in 1962, became an operative in 1986 for the KGB, continuing when it changed into the FSB in 1991. Until the mid-1990s, he remained a loyal employee. But participation in Russia's war with Chechnya disillusioned him as he witnessed the official lies and murderous behavior of Russian forces.

The turning point came in 1997. Ordered by the FSB to kill Boris Berezovsky, the influential oligarch and Kremlin adviser, he instead warned Berezovsky, then held a televised 1998 Moscow news conference at which he and several disguised FSB mavericks made the charges public.

From then on, Litvinenko became a despised enemy of Russian intelligence and, many believe, of current Russian President Vladimir V. Putin, himself a fiercely loyal veteran of the KGB and FSB.

The government fired Litvinenko from the FSB, and arrested and tried him in 1999 on minor charges. But in 2000 he escaped from Russia with his wife, Marina, and son, Tolik, ultimately receiving asylum in Britain.

In the years between his arrival in Britain in 2000 and death in 2006, Litvinenko evolved into a loyal aide to Berezovsky, also by then an exile in Britain and Putin's foremost enemy. Litvinenko published two books with sensational claims: Blowing Up Russia (2001) and The Gang From Lubyanka (2002).

Litvinenko asserted that the FSB had itself blown up Moscow apartment buildings in 1999, killing scores, to justify a renewed war against Chechnya and to bolster support for the newly installed Putin. He also alleged that the infamous Moscow "theater siege" of 2002 was an FSB operation. Several Russian politicians and journalists who tried to investigate those allegations were later murdered, including Anna Politkovskaya, shot to death last year on Putin's birthday, Oct. 7.

On May 22 of this year, after a Scotland Yard investigation, Britain charged that former KGB agent Andrei Lugovoi poisoned Litvinenko on Nov. 1, 2006, by placing polonium-210, an extraordinarily deadly substance, in his tea at London's Millennium Hotel. Twenty-three days later, Litvinenko died an excruciatingly painful death.

On his deathbed, according to intimates, including Alex Goldfarb, coauthor with Litvinenko's wife of one of two new books on the affair, he wrote a powerful statement accusing Putin of his murder. ("May God forgive you for what you have done, not only to me, but to beloved Russia and its people.")

Also at that final stage of Litvinenko's life, British doctors made the astonishing discovery that the poison was indeed polonium-210, an element difficult to detect at first, but a godsend to detectives because it leaves an unmistakable radioactive trail.

As a result, Scotland Yard pinned the crime on Lugovoi and demanded his extradition from Russia. Russia refused.

A few weeks ago, Britain ejected four Russian diplomats, a traditional Cold War rebuke, and clamped down on visas for Russian officials. Russia responded tit for tat.

That leaves British relations with Russia at their frostiest in decades. By contrast, Bush recently hosted Putin at his family compound for the fraternity-brother diplomacy he favors.

Death of a Dissident and The Litvinenko File offer compelling though different accounts of this intricate affair.

Martin Sixsmith, a former Moscow BBC correspondent, brings a deductive Holmesian style and reportorial distance. He synthesizes biographical and other information about the main players, concluding that an independent group of current or former FSB agents, acting without direct orders from the Kremlin (but knowing their work would be appreciated), committed the murder. He has done excellent reporting and is often skeptical of claims by Berezovsky and Litvinenko.

Goldfarb and Marina Litvinenko, by contrast, couldn't be closer to the subject, and their book is by far the more exciting read, a riveting thriller full of eyewitness accounts.

Marina Litvinenko's sympathies require no explanation. Goldfarb is an ex-Russian scientist who emigrated to the United States, became chief steward of philanthropist George Soros' projects in Russia, started working for Berezovsky in the mid-1990s, then flew to Turkey (at Berezovsky's behest) to help in the Litvinenko family's escape.

Goldfarb argues that only Putin could authorize and orchestrate a "polonium" murder, given the immense difficulty involved in obtaining and using the rare substance, 97 percent of which is produced in Russia.

One cannot remotely lay out, in this limited space, the rich "inside Russia" detail both books provide for making up your own mind.

Perhaps the most important context both books deliver is that all the characters in this drama knew or know one another, in some cases quite well. Berezovsky, once a close adviser to Boris Yeltsin, skied and dined with Putin and pushed him as Yeltsin's successor before they fell out. Litvinenko personally brought a dossier of criminal FSB activities to Putin in 1998 in the hope that the latter, then running the FSB, would reform it. (Litvinenko later concluded Putin couldn't because he participated in criminal FSB activities himself.) Lugovoi once worked for Berezovsky as security head for ORT, his TV channel.

Those connections make unconvincing the official Kremlin notion that Litvinenko was too insignificant a figure to bother the Kremlin.

Absorbing both these books resembles downing one's skulduggery straight, on an empty stomach, without any "sweeteners." Whichever scenario you accept, one thing's for sure:

The 1990s Western hope for a free, democratic Russia has gone up in smoke - or radiation.

Who lost Russia? The West did. The consequences are just beginning to play out.