Within that exclusive group of literary characters who have survived through the centuries--from Hamlet to Huckleberry Finn--few can rival the cultural impact of Sherlock Holmes. Since his first public appearance 20 years ago, the gentleman with the curved pipe and a taste for cocaine, the master of deductive reasoning and elaborate disguise, has left his mark everywhere--in crime literature, film and television, cartoons and comic books.Conan Doyle was born in Edinburgh in 1859, in a middle-class Catholic family, they moved frequently in search of lower rents; and his father, a civil servant and illustrator was an alcoholic who had to be institutionalized. At 14 came his first unforgettable visit to London, including Madame Tussaud's, where he was "delighted with the Horrors, and murderers."Conan Doyle went on to medical school, where he was attracted by Dr. Joseph Bell, a professor with an uncanny ability. In 1886, Conan Doyle outlined his first novel, A Study in Scarlet, its main charac