LONDON  Julian Assange, the founder of WikiLeaks, will release an autobiography next year, having signed publishing deals that he told a British newspaper might be worth $1.7 million.

Mr. Assange told The Sunday Times of London that he had signed an $800,000 deal with Alfred A. Knopf, an imprint of Random House, in the United States, and a $500,000 deal with Canongate books in Britain. With further rights and serialization, he told the newspaper, he expected his earnings to rise to $1.7 million.

Paul Bogaards, a spokesman for Random House, said Monday that the book would be “a complete account of his life through the present day, including the founding of WikiLeaks and the work he has done there.” The deal, Mr. Bogaards said, was initiated by one of Mr. Assange’s lawyers in mid-December and was signed in a matter of days. He would not discuss the financial terms. Canongate has not yet made a public comment but has spoken of its own deal in messages on Twitter.

“I don’t want to write this book, but I have to,” Mr. Assange told the newspaper, explaining that his legal costs in fighting extradition to Sweden, where he is wanted for questioning about allegations of sexual misconduct, have reached more than $300,000. “I need to defend myself and to keep WikiLeaks afloat,” he said.