Mr Brown discussed Britishness with author Ian Rankin
He may have his hands full with economic crises and leadership worries, but it seems Gordon Brown can still find time for a spot of writing.
The prime minister is preparing to write his third book in four years, he revealed at the weekend.
The book, which will include a contribution from Harry Potter author JK Rowling, is on being British.
Mr Brown's previous titles include Courage: Eight Portraits and Britain's Everyday Heroes.
Bill Campbell, founder of Mainstream Publishing in Edinburgh, of which Mr Brown used to be a director, revealed the PM's latest title was scheduled to be published in February 2009.
He said: "It was an original idea from Gordon and there has been a substantial personal contribution from him.
"He has approached several archbishops and other religious leaders for their views, and Ian Rankin, J.K. Rowling and Sir George Martin are among the other contributors.
"It's quite a wide list and the book is meant to reflect on the diversity of what it means to be British in the modern day."
The book will be edited by Matthew D'Ancona, editor of the Conservative-supporting Spectator magazine, the publishers said.
Defending his controversial 'Britishness' agenda, the prime minister said historians believed only 3% of Scots had English relatives in 1707, the year of the Union between the two nations.
There was very little contact, and most Scots had nothing to do with their neighbours south of the Border.
"Today, it's an amazing fact that 50% of Scots have close relatives in England, so it seems strange that people are talking of splitting up when there's such a level of connection at a human level at a family level with England," he said.
"Then you've got to look at what holds us together. People say the Empire, the benefits of industrialisation, the war years that we went through together. I don't think that's the case.
"I think we share the same values about liberty, about democracy, about the need for social cohesion and for people to work together co-operatively.
"I think we share respect for similar institutions like the health service.
"I wouldn't like to see health care denied to a Scot in England or to an English person in Scotland.
"I think the principle of the health service we all accept is the right to health care in any part of the United Kingdom, the right to work in any part of the United Kingdom, the right to attention no matter which part of the United Kingdom you live in."
'Too little, too late'
Mr Brown discussed being British with the best-selling crime writer Ian Rankin at the Edinburgh International Book Festival.
Asked how he found the time to write, he said: "I get up early and write first thing in the morning.
"I type with two fingers - it can be as unintelligible as my hand writing."
But his continuing interest in the subject of Britishness was ridiculed by the SNP leader, Scotland's First Minister Alex Salmond.
A spokesman for Mr Salmond said: "For poor old Gordon Brown this may be too little, too late.
"His Britishness campaign has always been about him trying to sell himself to people south of the border, especially Middle England.
"What they want from the prime minister is a decisive government dealing with the economic crisis, not a floppy identity campaign."