The BBC say that this week’s episode of Sherlock will see him face to face with Moriarty.  So far Gatiss and Moffat have done a good job so I hope they don’t make a mess of this.With all the fuss about Moriarty and his reputation as Sherlock Holmes’s arch enemy and nemesis it is easy to forget that he only featured in two of the 60 stories that Conan Doyle wrote, although he was mentioned in a few others.

I suppose it must be a credit to Conan Doyle’s writing that a character should grab the public’s imagination so strongly in so few words, but although our imperfect memory might let us see the story of Holmes as a struggle between him and Professor Moriarty the books themselves featured the struggle between Homes and Scotland Yard as much more of a theme.

Of course, not all the credit can go to Conan Doyle.  The reason Moriarty is such a well-known villian is as much due to all those who wrote homages, pastiches and sequels.  Although Moriarty only appears in 3% of the original stories he probably appears or gets mentioned in at least half the stories by other authors.

And in the films.  And films have much more of an impact on the general public – defined as normal people as opposed to us Sherlock Holmes anoraks.

So what I am worried about is Moffat and Gatiss falling into the same habit and making Moriarty much more of a presence in the TV series, which I suppose they have already done.  It occurs to me that Moffat in particular is used to the idea of having an overall story arc to a series – as we have seen with the relaunched Doctor Who.  Sherlock holmes was always a series of self-contained stories with no overall narrative.

I think the only time a story really followed on from another was when The Empty Housefollowed on from The Final Problem – but having killed Holmes off Conan Doyle could hardly continue without some sort of explanation.  Some of us quite like having the stories discrete like that, so you can dip into any of them in any order, like the Jeeves and Wooster stories.

My other worry is that the writers will be tempted to add some sort of twist, like having Moriarty turn out to be Mycroft.  Having read stories where Moriarty turns out to be Jack the Ripper, Holmes turns out to be Moriarty, Watson turns out to be Jack the Ripper – and even where Mrs. Hudson turns out to be Jack the Ripper – I know that writers find it hard to resist putting a little twist in.  That is fine in a one-off story, but more of a problem if you intend to carry on a series and will have to live with the twist you put in.

So far the treatment has been quite sympathetic, so there is every chance things will remain sensible.

Talking of Moriarty, I can thoroughly recommend the Moriarty books by John Gardner.  They were supposed to be a trilogy but only two books were published in the 1970s.  I gave up any hope of reading a third and only recently found out that the final book was published a couple of years ago, shortly after Gardner died.