The former chancellor left government in July and said last month that it was too early to write his memoirs as he did not know "where his story ends".
Instead, he will pen a book entitled the Age of Unreason, examining the rise of "populist nationalism" embodied by Donald Trump's US presidential bid.
Ed Balls, Nick Clegg and Ken Clarke have all recently released memoirs.
Despite losing his job as chancellor after Theresa May became prime minister, Mr Osborne has said he will remain in politics to fight for the values he believes in and will contest the next election.
Announcing the project, which will take a year, Mr Osborne called for the forces of free markets and open society to take back control of the political debate.
Mr Osborne said: "My book is about the future. I want to apply the lessons I've learnt in victory and defeat to the urgent challenge of this Age of Unreason.
"Capitalism and democracy is in crisis. The West is in retreat. The forces of populist nationalism and prejudice are on the rise, amplified by new technology. The likes of Donald Trump say to people, what the hell have you got to lose. The answer is, a lot. Peace, prosperity and security.
"It's time to say so. It's time for the defenders of open societies and free markets to fight back."
George Osborne is to write a book which will explore the background to the "crisis in democracy and capitalism".