The publishing industry like most businesses is struggling in the recession, but one type of book has been selling as quickly as it could be printed - the celebrity memoir. The autobiographies of Paul O'Grady, Dawn French, Julie Walters, Michael Parkinson and Alan Carr have now sold over two and a half million hard back copies between them. Unusually for this genre, the books are self-written and genuinely revealing. In a special edition of Front Row, Mark Lawson speaks to these authors - and others - about why they decided to set down their lives.