An untouched copy of Harry Potter and the Philosopher's Stone that has been preserved in pristine condition in a loft for almost three decades is expected to sell for £10,000 at auction. The scarce first edition - which originally retailed for just £4.99 when it hit shelves in 1997 - has been described as "the finest example ever to come to market". The paperback was sent to Katrina McNichol, who was employed as a book reviewer for a magazine in the Scottish Highlands during the late 1990s.