Tony Blair's memoirs, based on his time as the prime minister, have broken sales records, booksellers have said.
A Journey became Waterstone's fastest-selling autobiography ever and shot to the top of Amazon's best-seller list.
Mr Blair's account of his time in Downing Street sold more copies on its first day of publication than David Beckham and Russell Brand's autobiographies.
It is currently the 12th best-seller in the US and 9th in Canada.
However, readers in France and Germany were not quite as interested, as the book only ranked 366th and 529th respectively.
Although Waterstone's refused to disclose precise sales figures, a spokesman said the book had been a "stupendous" and "unprecedented" success.
He added: "We've never seen a book like this sell so quickly in one day. It's selling in the sort of numbers you don't see outside of mass market fiction with huge appeal - Dan Brown and JK Rowling are the competition here.
The chain said it sold as many copies of A Journey on Wednesday as it did of former business secretary Lord Mandelson's memoirs The Third Man in three weeks.
Official sales figures will not be released until next Tuesday.
The memoirs include Mr Blair's accounts of the Iraq war, the 9/11 terrorist attacks in America and Princess Diana's death.
He also wrote about concerns over the amount he was drinking and of the rift he had with his successor Gordon Brown.