A self-confessed smart aleck, radio host, documentary maker and author, John Safran makes a point of poking people and getting himself into difficult situations.

But being Jewish and hanging out with neo-Nazis begins to take its toll after a while. As do text threats.

“Things got to me, definitely,” he acknowledges as we meet at his local café in the heart of Melbourne’s Orthodox Jewish community. It’s something of an understatement, I suggest.

Halfway though his startlingly good, stereotype-smashing new book Depends What You Mean by Extremist (out May 1), Safran starts to carry a concealed knife.

“I’m going through the madness and everyone’s contacting me all the time and I’m getting paranoid,” he says. “Some of the messages pinging on my phone were threats.”

Softly spoken and perhaps even a little shy in person, thankfully the knife carrying didn’t end up heading anywhere dark.

As Safran jokes, “You’re hanging out with neo-Nazis, you can’t act all act all surprised when they get anti-Semitic.”

There’s definitely a fire at the heart of his book, which examines radicalisation in all its sometimes surprising forms.

There’s Pastor Daniel Nalliah, a Sri Lankan immigrant whose evangelical Christian Catch The Fire Ministry, with many Asian, Indian and African followers, supports the anti-Muslim stance of Reclaim Australia.

Or there’s the publicity-hungry Avi Yemini, the Arabic Jewish gym owner and former Israel Defense Force soldier who condemns Islamists and peace activists who burn the Israeli flag, but offers to burn the Palestinian one for Safran as “colour” for his book.

And then there’s the Monty Python-loving Muslim convert Musa Cerantonio. By the end of the book he will stand accused of attempting to fight overseas for an ISIS-related terrorist group. Safran says of him, “with his white skin and Aussie accent, he could be an Alan Jones talkback caller”.

Take your pick, there’s plenty more out-there moments, like Safran’s family connection to the secretive and possibly radically Jewish, anti-Islamic Q Society.

Finding out one of them knew my dad when they were little kids, that was like, ‘what the hell?’

“Finding out one of them knew my dad when they were little kids, that was like, ‘what the hell?’ Are we all sort of victims of our own tribalism?”

A razor-sharp read, Safran takes no sides or prisoners, just as willing to point the finger of blame at the constantly and sometimes hypocritically outraged left.

“The thing that kind surprised me most was what I wasn’t allowed to say to the lefties who were fighting against racism.

“Isn’t it interesting that people can be victims of racism, but they can be racist themselves?'” Safran says, referring to an incident where a man who was the target of Islamophobic abuse also made an anti-Semitic comment.

“You just weren’t allowed to go there,” Safran says. “I found that a bit disturbing. It’s a bit like being in a cult, because I’ve done a lot of hanging around religions and the thing that makes cults different is that you’re not allowed to say stuff.”