Conan doyle wrote many different kinds of books. Some of them, like The Exploits of Brigadier Gerard (1896) and other "Gerard" stories, were historical.He wrote a number of science fiction books about a man called Professor Challenger.He also wrote about war.During the Boer War (1899-1902),when the Boers fought against the British in South Africa,many lives were lost.Conan Doyle worked in hospital there and wrote The Great Boer War (1900)