Andy McSmith: An extraordinary story, lovely writing and a weirdo hero – what's not to like?

Assange relates that one Christmas he and his son blew up Barbie dolls with homemade explosives

One reason Julian Assange is left with the feeling that all mainstream journalists are "wankers" is the way that we focus only briefly on the information that WikiLeaks puts into the public domain before turning to the subject of – I quote – "how weird" he is.

He has a point. The scale of what he and his ragged army of volunteer computer geeks achieved in exposing things the US government wished to conceal is monumental. Assange personally worked so hard and so obsessively to expose the secrets revealed in that infamous "Collateral murder" video that, he says, he had his hair cut sitting at his computer.

He could have made millions out of his IT skills, but he did not want money. Instead he has lived an outlaw's life, devoted to a single aim, with influential people in the US implying he deserves to be killed.

That said, he is very, very weird.

The reason he disowned Julian Assange, the Unauthorised Autobiography, so creating a whole new genre in retracted self-revelation, seems to be that he realised too late just how much he was revealing. The extract in today's Independent is a glimpse into his peripatetic childhood, which denied him the chance to learn how to relate to people of his own age.

There were other girls, apart from the classmate whom he whacked with a hammer, though he says little about them. He had a son, and believes he was a good father. His methods of bonding were unconventional. He relates: "At Christmas one time, we gathered Barbie dolls and toy dragons and blew them up with some home-made explosives and liquid nitrogen."

In his teens he acquired his first computer and modem. He writes about their impact on his life like an adolescent who has entered a religious cult. "It was the computer I spoke with, or spoke through, reaching past all concerns to an infinity point where selfhood dissolves into history."

He enjoyed the idea that people he passed in the street would think he was just another "slacker teenager" unaware that he was up all night, every night, in his bedroom, hacking Nasa's computers.

"I am amazed when I run into people who don't understand the pleasure of this, for it is the pleasure of creation itself," he writes.

We know where this adolescent obsession took him – to the creation of WikiLeaks, to Sweden, where he hoped to be able to end his wandering life and open an office, and into bed with two women who are now accusing him of rape – a charge of which I very much doubt any British jury would convict him. He admits that his behaviour towards them "sounds cold", that "I wasn't a reliable boyfriend, or even a very courteous sleeping partner" and that "I may be a chauvinist pig of some sort, but I am no rapist."

I believe him, because the "unauthorised autobiography" draws a picture of someone highly intelligent, widely read, with a fine memory for sights, sound and incidents and a genius with computers, but zero understanding of his fellow human beings. There are almost no people in this book apart from Julian and individuals who have caused him grief or let him down. The one person he thinks he understands well is himself. "I know my faults", he writes, and at different places in the book he describes himself as "a bit autistic", "addictive", "paranoid" and "some kind of weirdo".

It is not hard to see why Assange is now fretting that, in this text, beautifully crafted by Andrew O'Hagan, he has given away too much of himself and said too little about his mission. That is exactly what makes the book such an engrossing read.