If you’re an aficionado of murder mysteries and have an hour to spare in London, you might like to pop into the British Library in St Pancras.  Their exhibition ‘Murder in the Library: An A-Z of Crime Fiction’ takes you alphabetically through some of the greats of the genre.  First editions galore, snippets of info possibly new to you (did you know Martina Navratilova wrote in the genre?), Fr Ronald Knox’s Ten Rules of Detective Fiction, and much more.  There’s a Conan Doyle manuscript of a Sherlock Holmes story that’s as easy to read as print (and he was a doctor …).  Enjoy.  It’s free, and is on until 12 May.  Find out more at http://www.bl.uk/whatson/exhibitions/murder/index.html.