I had no idea that such individuals exist outside of stories.

Arthur Conan Doyle (1859-1930) British writer and physician

Story (1886-04), “A Study in Scarlet,” Part 1, ch. 2 [Watson], Beeton’s Christmas Annual, Vol. 28 (1887-11-21)
    (Source)

Watson to Holmes, comparing him to Edgar Allan Poe's Dupin (a comparison that Holmes sniffs at).

Published in novel form 1888-07.