Whistler and Collins.

Collins's Woman in
White with Whistler's
White Girl on cover

The online edition of the letters of artist James McNeill Whistler features a few letters concerning attempts to link Whistler's The White Girl (1862) to Wilkie Collins's Woman in White (1859–60), a letter that reveals that Whistler liked Mary Elizabeth Braddon's The Golden Calf (1883), and witty correspondence from Oscar Wilde. It looks like the 1906 letter from Arthur Conan Doyle is not yet online.