I have a very clever question planned to wrap up my interview with author and journalist Jon Ronson, who has made his name travelling the world in the company of extremists of various stripes and writing about them in a faux naive style that in equal parts exposes both humanity in very unexpected places and terrifying zealousness where you might least expect it.

I am going to finish the interview by asking Ronson if, by gently lampooning some of the most enduring conspiracy theories and the people who posit them, by painting the cult leaders and the terrorists and the mysterious groups who might or might not rule the world in a sometimes mundane light, if he isn't in fact playing right into their hands.

If Ronson is holding a light up to these shadowy, paranoid theories and saying: "Look, aren't there just normal people with pretty funny ideas at the bottom of it all?", isn't he actually part of the conspiracy and doing their work for them by telling his readers that there's actually nothing funny going on?

Ronson proves himself as clever as he comes across in his writing, because he deftly pulls my rug out from under me by addressing this very point in the middle of something else, showing that there isn't anything that he hasn't already considered himself.

A popular columnist with the Guardian and a freelance journalist and film-maker, Ronson, 39, has had two books published: Them: Adventures With Extremists, and The Men Who Stare At Goats. They are, by turns, hugely funny and incredibly unsettling. He allows us to accompany him into the heart of Ku Klux Klan territory, we are introduced to a jovial Muslim who has been branded the most dangerous man in Britain, and very serious military men talk in very serious tones about very serious experiments they have carried out to kill goats simply by staring at them a certain way.

His third book, published today by Picador and Guardian Books, is called Out of the Ordinary, and at first glance it treads slightly different ground to his previous ones. It is ostensibly a collection of his columns and journalism from the Guardian's Weekend magazine, and as such tends to focus more on his day-to-day life with his son Joel and wife Elaine, rather than the over-arching world conspiracy stuff.

"I started my Guardian column about four years ago," he says, marching through London from his home on a 90-minute walk to the Channel 4 offices. "I'd been writing for 15 years about other people, about craziness on the fringes, and I suppose the columns are more about the stuff that's happening right in front of me."

Which, he says, is no less crazy; it's just craziness on a smaller scale. His little vignettes of life at Chez Ronson are sometimes excruciatingly embarrassing as he lays bare his own behaviour and the inner frailties of his character. Does he ever have qualms about giving so much information about his personal life when he's mixed with some of the world's most dangerous people?

"Do you mean, am I worried that someone will kidnap Elaine or Joel?" he says, as though it's the first time the thought has crossed his mind. He ponders it and says: "I think it's very unlikely. I used to get worried about stuff but then I realised it was stupid."

But there must have been some hairy moments during his travels with extremists, surely.

"I think I was most scared when I was chased by the Bilderberg Group," says Jon. The episode appears in Them, when Ronson teams up with a conspiracy theorist to track down the supposed meeting place of the world's most influential people, who are alleged to control every aspect of our lives. After finding the hotel where they are meant to be gathering, Jon and his colleague are followed by shadowy figures. "It was terrifying."

Inevitably, his writings attract the attention of conspiracy theorists, many of whom flock to his website to posit their own ideas, largely about the 9/11 attacks. He has little truck with them, mainly for their single-minded view of life.

"I like to think of myself as a rationalist," he says. "I'm quite sane and liberal and I think people like this are irrational." He pauses then goes on: "But there's also a school of thought that rational people are bullies, they start picking on people who actually have beliefs because they think they're above that sort of thing."

It's around this point that he mentions that the conspiracy theorists often say he himself is part of the conspiracy because of his honest and guileless approach to the extremists, the cult leaders, the fanatics and the fascists. I quietly cross out the question on my notepad.

Ronson is mindful that his columns (and his longer journalism, including a fascinating profile of disgraced pop impresario Jonathan King, which also appears in the new book) and what he calls his "extremist" stuff might have different audiences, but he is convinced there's a lot of crossover potential.

"One day I might be writing about domestic craziness the next I might be jumping on a plane to hang out with the Klan. At the end of the day, it's all about people."

l Out of the Ordinary by Jon Ronson is published today by Picador, priced £8.99. He is appearing at Waterstone's bookshop in Leeds centre on Wednesday, November 15. The event starts at 7pm and tickets cost £3. For details call (0113) 244 4588.