The book, provisionally entitled Back from the Brink, will focus on 1000 days around the crisis of 2008.
Due out next September, it will also include his reflections on other key events during his three-year tenure as Chancellor and his earlier career.
But the Edinburgh South West MP said he was not interested in a "kiss and tell" book about tensions inside the Labour government.
He said: "I want this to be a book people will come back to in ten, 20 or 30 years' time."
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Toby Mundy, chief executive of publishers Atlantic Books, said: "Not only will Alistair Darling's book be a gripping drama, but it is also a vital historical document. It will take a story that people think they know something about and make us see it afresh, from the perspective of someone at the epicentre of the storm."
Mr Darling, who decided to return to the backbenches after this year's general election, is still adjusting to life in opposition after 13 years in government.
He said: "Of course, it's a huge change.
"I don't miss the trappings of office, but I enjoyed the challenge. I've always enjoyed hard work. Getting up early in the morning, going to bed late at night - I don't mind that."
But he said he did not miss having to plough through ministerial papers every weekend.
"I prefer pruning roses."
The former tenant of 11 Downing Street is now based in a fifth-floor office in Portcullis House, an annexe to the Houses of Parliament.
He says he enjoys being able to walk to work and he is pleased to be able to devote more time to his constituency.
"I'm usually in London Monday to Thursday, but come the weekend I can commit to doing things in Edinburgh.
"Knowing I can be in Edinburgh most weekends is a huge plus. At the height of the crisis, I was having to fly up, do a surgery and fly back down again."
Being on the backbenches also allows him to pick and choose what he speaks on in the Commons.
He said he tried to avoid territory which might cause awkwardness for his successor as shadow chancellor, Alan Johnson. "Alan is doing a very good job. He's different in style but he and I see very much eye to eye on the key issues."
Mr Darling backs the coalition government's decision to help with the bail-out of the crisis-hit Irish economy.
But he remains highly critical of the government's approach to the economy.
"My fear is it's not just the economy that's at risk, but the social fabric of the country.