What area of study did Sir Arthur Conan Doyle specialise in?

He wrote more than 20 novels and 100 short stories, also 81 poems, 12 plays, and 12 pamphlets with themes OTHER than Sherlock Holmes. He participated in the sports of football (soccer), cricket, Golf, and downhill skiing. He even played a role in popularising the sport of downhill skiing, or what he called ski-running, in the UK and Switzerland. He was an amateur detective who helped to clear the names of two people. He was an avid freemason and spiritualist. He ran for Parliament twice, unsuccessfully.