Profile: Wikileaks founder Julian Assange
To his fans, Julian Assange is a valiant campaigner for truth. To his critics, though, he is a publicity-seeker who has endangered lives by putting a mass of sensitive information into the public domain.
Mr Assange is described by those who have worked with him as intense, driven and highly intelligent - with an exceptional ability to crack computer codes.
He is often on the move, running Wikileaks from temporary, shifting locations.
He can go long stretches without eating, and focus on work with very little sleep, according to Raffi Khatchadourian, a reporter for the New Yorker magazine who spent several weeks travelling with him.
"He creates this atmosphere around him where the people who are close to him want to care for him to help keep him going.
"I would say that probably has something to do with his charisma."
Julian Assange has been reluctant to talk about his background, but media interest since the emergence of Wikileaks has given some insight into his influences.
He was born in Townsville, Queensland, northern Australia, in 1971, and led a nomadic childhood while his parents ran a touring theatre.
He had a child at 18, and custody battles soon followed.
The development of the internet gave him a chance to use his early promise at maths, though this, too, led to difficulties.
In 1995 he was accused with a friend of dozens of hacking activities.
Though the group of hackers was skilled enough to track detectives tracking them, Mr Assange was eventually caught and pleaded guilty.
He was fined several thousand Australian dollars - only escaping prison on the condition that he did not reoffend.
He then spent three years working with an academic, Suelette Dreyfus, who was researching the emerging, subversive side of the internet, writing a book with her, Underground, that became a bestseller in the computing fraternity.
Ms Dreyfus described Mr Assange as a "very skilled researcher" who was "quite interested in the concept of ethics, concepts of justice, what governments should and shouldn't do".
This was followed by a course in physics and maths at Melbourne University, where he became a prominent member of a mathematics society, inventing an elaborate maths puzzle that contemporaries said he excelled at.
He began Wikileaks in 2006 with a group of like-minded people from across the web, creating a web-based "dead-letterbox" for would-be leakers.
"[To] keep our sources safe, we have had to spread assets, encrypt everything, and move telecommunications and people around the world to activate protective laws in different national jurisdictions," Mr Assange told the BBC earlier this year.
"We've become good at it, and never lost a case, or a source, but we can't expect everyone to go through the extraordinary efforts that we do."
Daniel Schmitt, a co-founder, describes Mr Assange as "one of the few people who really care about positive reform in this world to a level where you're willing to do something radical to risk making a mistake, just for the sake of working on something they believe in".
Wikileaks has published material from a number of different countries, but really hit the headlines in April, when it released video taken from a US helicopter in Iraq in 2007. The images, carried by media outlets around the world, caused widespread shock.
Mr Assange emerged into the spotlight to promote and defend the video, as well as the massive releases of classified US military documents on the Afghan and Iraq wars, in July and October.
But reporters say he can still prove elusive, and that the workings of his website remain shrouded in secrecy.
In another twist in a controversial career, he is the subject of an international arrest warrant issued by Swedish prosecutors over allegations of rape and molestation.
The claims surfaced after he visited Sweden in August and relate to separate sexual encounters with two women, which his lawyer says were entirely consensual.
Mr Assange says the allegations are part of a smear campaign against him and his whistle-blowing website.
An initial investigation in August was dropped after only a day, but in September Sweden's Director of Prosecution reopened the case.
On 24 November, a Swedish court rejected his appeal against a detention order. The case is currently being considered by the Supreme Court.
Following the Wikileaks release of thousands of classified US diplomatic cables, the deputy foreign minister of Ecuador - a strong opponent of US policy - said it would offer Mr Assange residency "without any conditions".
However, Ecuador's President Rafael Correa later said the offer had "not been approved by Foreign Minister Ricardo Patino - or the president".