It's not quite the career trajectory you'd expect from a guy like David Talbot. In 1995, after years as a newspaper features editor in San Francisco, he caught a whiff of the possibilities of the Internet well ahead of his peers, created the online magazine Salon and spent the next decade watching the enterprise ping between journalistic success and financial near death.

Then, two years ago, just as Salon turned a profit for the first time, Talbot stepped down from day-to-day operations, announcing he would engage in that most mainstream of media pursuits: writing a book. But this would not be a memoir - no pithy retelling of his hair-raising adventures as a not-so-ink-stained Internet pioneer. Instead, last month he published a sober, 400-page re-examination of United States president John F Kennedy's assassination, Brothers: The Hidden History of the Kennedy Years.

In Brothers, Talbot uses Bobby Kennedy's conflicted response to his brother's murder as a lens to examine the crime and various theories about how it happened. Although Bobby Kennedy, who was his brother's attorney general, often seemed publicly to agree with the Warren Commission's lone-gunman conclusion, privately, Talbot writes, he didn't believe it. Talbot concludes that Bobby was in fact the country's first Kennedy conspiracy theorist, and that had he been elected president in 1968, he might have been able to solve the crime once and for all. "Bobby felt this plot came out of the CIA's secret war on Castro," says Talbot in Los Angeles.

This is not Talbot's first public foray into big-splash political writing. He made national waves in 1998, when, during former president Bill Clinton's impeachment, Salon published a story about a 30-year-old extramarital affair by US Representative Henry Hyde, then the Republican chairman of the House Judiciary Committee. Defending his much- vilified decision, Talbot memorably wrote: "Aren't we fighting fire with fire, descending to the gutter tactics of those we deplore? Frankly, yes. But ugly times call for ugly tactics."

There might not always be a Kennedy in public office, but it seems there will always be someone, somewhere, working on a Kennedy book. Talbot, who lives in San Francisco with his wife, writer Camille Peri, and their two teenage sons, says he was always curious about what Bobby Kennedy really thought had happened in Dallas, and was nudged toward the book by a friend who reminded him that for the remaining Kennedy contemporaries, time was running out.

"I can't paw through documents," Talbot says. "I am a journalist, I needed to sit down and talk to Kennedy administration people who had a living link to the story." Some people he interviewed - presidential adviser Arthur M Schlesinger Jr and the investigative journalist Jack Newfield - died before the book came out.

He also spent time with JFK's legendary speechwriter Ted Sorensen; his defense secretary, Robert McNamara; and journalist Ben Bradlee (with whom he had a pointed conversation about why Bradlee, one of JFK's closest friends, and who would take the reins at the Washington Post in 1965, did not pursue the assassination story with more vigor. Bradlee admitted that while it "would have been fantastic (to have solved the crime)," he didn't unleash the Post's considerable investigative muscle on the story because he was afraid he'd be discredited for taking the Post "down that path").

Talbot, 55, dates his interest in the Kennedys to his teenage years. When John Kennedy died, Talbot, then 12, was a student at the Harvard School for Boys, a private Los Angeles military school. Home was a conflicted political environment. His father, actor Lyle Talbot, was a Republican, a friend of Ronald Reagan's and a co- founder of the Screen Actors Guild. His mother, Paula, a former showgirl, was an ardent Democrat.

"Harvard was a pretty Republican school," Talbot says. "I was in Latin class when it was announced that JFK was assassinated. There were cheers in the classroom. It was eerie. But you have to remember - Southern California was a hotbed of John Bircher-, anti-Kennedy feeling."

The publication of Talbot's book coincides with the arrival of another JFK murder inquiry - Vincent Bugliosi's Reclaiming History: The Assassination of President John F Kennedy.

When Talbot stepped down from Salon to launch his Kennedy research, incidentally, Bugliosi had been at work on his book for 18 years. Bugliosi's painstaking effort (and, at 1,600 pages, painfully long in the view of some reviewers) reaches an opposite conclusion. While Talbot makes a familiar argument that a confluence of anti- Castro Cubans, rogue CIA elements and the Mafia were behind Lee Harvey Oswald's murderous act, Bugliosi insists there was no conspiracy, that Oswald acted alone (and that anyone who doesn't understand that is a fool or worse). Talbot is not so dismissive, however, and says he is trying to arrange a verbal duel with Bugliosi to be held in public. (So far, no response from the Bugliosi camp, Talbot reported.)

"This whole area is a rabbit hole, a dark labyrinth, and I was determined not to get lost in it," Talbot says over coffee. "I think Vincent Bugliosi got lost in it. My way was to use Bobby Kennedy as a light, and to explore what he thought happened. I think he was looking at the CIA and their secret war on Castro in which they used militant Cuban exiles and mobsters to carry out their dirty work. I think Bobby thought that was the operation that turned its guns against JFK."

Talbot marshals the evidence and presents it engagingly, but nothing can be proved because many of the principals have died of old age (or died early under mysterious circumstances); many CIA files are still under lock and key and there has been little political will to reopen the wound with a formal investigation. (This, says Talbot, despite the fact that nearly three-quarters of Americans polled said they believe a conspiracy was behind the JFK slaying. As recently as last year, almost two- thirds of Americans told pollsters they believed that Saddam Hussein had strong links to al-Qaeda, so maybe this is just an example of that famous American paranoid strain in politics rearing its ugly head.)

History buffs might know that John Kennedy thought it was possible that the Joint Chiefs of Staff could consider a coup under the right conditions, or that the CIA suspected he was being led down a path of "peace, love and drugs" by his mistress, Mary Meyer, the bohemian ex-wife of a CIA agent, who introduced him to marijuana and possibly LSD. Her 1964 death was never solved.

But for those with only a passing knowledge of the era, or who are wishing for a refresher course on the turbulent politics of the early Cold War or the stunning internecine battles waged during the Kennedy administration over commies, Cubans and civil rights, Brothers is a bracing retelling of a familiar tale, full of shocking moments and juicy tidbits. Talbot, naturally, hopes the book will find its way to the big screen. "Message to George Clooney," he says, with a chuckle. "I thought he would be perfect to produce it because his aunt, Rosemary Clooney, was singing at the hotel when Bobby was shot and had a terrible nervous breakdown afterward."

Meanwhile, although he helped invent the brave new genre of online journalism, Talbot never managed to get rich. Salon, where he is still chairman of the board, paid him a decent salary, according to news reports), and he says he ended up with something north of US$100,000 when he cashed out his stock. But, he says cheerfully, ink- stained wretch style: "I am an old- fashioned guy. I started out deeply in debt, and I'm still deeply in debt."

THE WASHINGTON POST