I’m not the only person whose work currently depends on following up the work of others authors. I’m certainly not the only Sherlock Holmes author – there’s hundreds of us. There are James Bond sequels (and prequels) and new Poirot and Lord Peter Wimsey books, and Jane Austen works.
There’s a certain responsibility when continuing the work of another author. The voice has to sound authentic. I don’t mean you have to write exactly like the original author, but it still has to sound like a story they had in mind. The characters still have to talk and think like they do in the original. I go over anything Sherlock Holmes says in my books again and again to make sure it sounds like him, and every time Mrs Hudson talks to him, I try to make it sound like it does in the original.
I think the best continuations are the ones that explore the original stories from another angle – from a background character, or a villain, say. These can be illuminating, but the truths they reveal still have to stay faithful to the original. The reader has to be able to read it and think ‘yes, I can see that in the original, now you mention it’
When I write the Mrs Hudson and Mary Watson mysteries, I feel I have a responsibility to Arthur Conan Doyle to stay true to his ideas. My characters have a basis in what he wrote, even is its only a line or two. My conception of Mrs Hudson is based on only a few moments in the original stories, but the moments are there. I have expanded on groundwork the original author laid, I hope.