by Sir Arthur Conan Doyle ; screenplay by Allan Cubitt ; produced by Christopher Hall ; directed by David Atwood ; a co production of BBC and WGBH Boston ; produced by Tiger Aspect Productions
directors, David Marks, Colin Murray, Kate Pringle, Lyndon Bruce, Danielle Peck ; executive producers, Jacqueline Smith, Paul Overton ; series producer, Matt Barrett ; BBC Studios, the Science Unit, Scotland