What Attracted Conan Doyle to the World of Spiritualism?

In the late 19th century and early 20th century, spiritualism became a growth movement. Conan Doyle's interest came about initially when he was a young, newly qualified doctor. He joined the Society for Psychical Research that Fiona mentioned in the 1890s. And at the time, the president was a man called Arthur Balfa, who later became British Prime Minister.