When Joey Dunlop, undisputed master of the Isle of Man TT, was killed in July 2000, some 50,000 well-wishers attended the funeral, which was broadcast live on Irish television. For the mourning motorcycle road race fans, he was akin to royalty. Mac McDiarmid's biography about the modest Ulsterman - packed with anecdotes, photographs and race information - has sold 19,000 copies since being published in hardback in May 2001.