The personal diaries of the late President Ronald Reagan covering his eight years as US leader are to be published next year.
Ronald Reagan wrote in his diaries every day of his presidency
He wrote in his diaries every day of his presidency, recording his thoughts on events both routine and historic, officials said.
Publisher HarperCollins called them "the most detailed presidential diaries in America's history".
Reagan died last year aged 93 after a long battle with Alzheimer's disease.
Before becoming the 40th president of the US, Ronald Reagan was governor of California from 1966 to 1974.
"When we left Sacramento [the state capital], we felt the time passed so quickly, we could hardly remember the eight years," said Nancy Reagan in a HarperCollins statement.
"When Ronnie became president [in 1980], he wanted to write it all down so we could remember these special times."
HarperCollins said it had signed a deal with the Ronald Reagan Presidential Library Foundation for world rights to publish the diaries.
They will be displayed at the presidential library in Simi Valley, California.
"Each day during his eight years in the White House, Ronald Reagan recorded his innermost thoughts and observations in his personal diary," said Frederick Ryan Jr, Chairman of the Board of Trustees for the Ronald Reagan Presidential Foundation.
"Although they were not initially intended for publication, we feel that these volumes offer an unprecedented insight into the Reagan presidency."