‘Sir Alex's book, Managing My Life, has sold 550,000 copies in hardback and paperback in three years. Around 500,000 copies of Keane's life story have been distributed in the UK and Ireland.
Retail experts say that his autobiography has already sold 100,631 over the counter up to last weekend after being in the shops for only two months. Publishers Penguin said that it had sold half a million copies through its distribution network and that sales should accelerate when the cheaper paperback version comes out.
The Irishman is expected to net £2m from sales of the book, which has remained in the best-seller list since it was published at the end of August. Rowland White, of Penguin Books, said: "As far as we know it's the fastest-selling book in Irish history. "The interest is unprecedented - we sold 80,000 copies in the first week alone and had to divert a lot of stock to Ireland."