My friend Philip Purser-Hallard has produced a really engaging and fun mystery for Holmes, published last year and part of the line of new Holmes stories from Titan Books. The basic idea - of a psychic who claims to be able to reach across space - feels very Conan Doyle and yet wholly original. It reminded me first of all of the "Victorian seance" performed by Derren Brown.
The strange assortment of characters seem authentically Doylish, too, as does the mix of the oddly comic and the outlandishly macabre. At times I was ahead of Holmes but there are a series of related mysteries and I didn't solve them all. They're all satisfyingly unthreaded by the end.
I especially liked the retcon of Holmes' ignorance of certain subjects that most people take for granted. That issue is described by Watson in chapter two of introductory story, A Study in Scarlet (1888):
"His ignorance was as remarkable as his knowledge. Of contemporary literature, philosophy and politics he appeared to know next to nothing. Upon my quoting Thomas Carlyle, he enquired in the naivest way who he might be and what he had done. My surprise reached a climax, however, when I found incidentally that he was ignorant of the Copernican Theory and of the composition of the Solar System. That any civilized human being in this nineteenth century should not be aware that the earth travelled round the sun appeared to be to me such an extraordinary fact that I could hardly realize it.Phil has Watson regret writing these words, with Holmes explaining:
'You appear to be astonished,' he said, smiling at my expression of surprise. 'Now that I do know it I shall do my best to forget it.'"
"'When specific knowledge is required of me, I am quite capable of acquiring it from the available sources. I would have been unable yesterday to tell you with any great certainty whether Venus was a planet, a comet or a star, but today I have at my fingertips such facts as are known about its magnitude, its periods of rotation and orbit, its atmosphere and its surface, in case these data should should become relevant to the matter at hand. Among other things, I have learned that Venus is judged by astronomers to be a younger world than our own, on the basis of its greater proximity to the sun, just as Mars is supposed to be older. That being the case,' he said languidly, 'the superior development that Kellway ascribes to its inhabitants appears to be rather anomalous.'" (p. 60)It's a simple, logical fix. It also nicely incorporates scientific thinking from the period (which we no longer think is right), and even better has Holmes use that as part of his deductions. Clever.