Julian Assange is self-consciously an individual. He thinks in his own way, primarily as a physicist, having studied pure maths and physics at university in Australia where he grew up.

So, for example, explaining his decision to found Wikileaks, he starts with his interest in the physics of a small release of energy triggering a much larger release; asks what small actions might release energy for "just reform"; identifies the role of information and observes the restriction on the amount of information flowing into the system; and sees Wikileaks as a mechanism "to maximise the flow of information to maximise the amount of action leading to just reform".

He also acts in his own way. Other people carry laptop computers; he carries a desktop machine in a rucksack on his shoulder. He will stay up all night, fingers flittering across the keyboard, and then suddenly crash out fully clothed in the nearest chair when everybody else is getting up. He is interested in "doing things that are not trivial or meaningless – making the most of your time".

Julian Assange, the founder of Wikileaks, explains why he decided to publish thousands of secret US military files on the war in Afghanistan guardian.co.uk

He reckons he is genetically predisposed to rebel. His parents met at a demonstration against the Vietnam war. His father, a lover of motorbikes who became an architect, taught him that "a generous, capable man protects victims and doesn't create them". His mother, as a teenager, rode her horse into city hall to protest against the closing of pony trails, and later took off on a motorbike for Sydney where she survived as a painter, actor and artist's model.

Assange's whole lifestyle is independent. At the age of 39, he has no home. Carrying his computer and a second rucksack with clothes, he moves wherever the cause takes him, usually arriving with no idea where he will sleep, a habit formed in childhood, when his mother's new career running a travelling theatre company saw him pass through 37 different schools.

In his late teens, he says he was part of the computer underground, working on early versions of the internet, hacking into the email of the power elite. An attempt to settle down to life as a university physicist ended, he says, when he discovered academic mathematicians and physicists were selling their discipline to military and intelligence agencies. He denounced them in a paper, "On the Take and Loving It", and set out to create a website as uncompromising as himself.