Sherlock Holmes Society of London: Chairman Elaine McCafferty welcomes members and guests (photo by Roger Johnson)
Sherlock Holmes Society of London: Elaine has handed over to Marcus Geisser, who will introduce this evening's speaker (photo by Roger Johnson)
Sherlock Holmes Society of London: Marcus Geisser and Michael Dirda became friends during Marcus's time in Washington, working for the International Red Cross (photo by Roger Johnson)
Sherlock Holmes Society of London: Michael Dirda takes the microphone (photo by Roger Johnson)
Sherlock Holmes Society of London: Professor Moriarty was not the only master criminal of his time (photo by Roger Johnson)
Sherlock Holmes Society of London: Some names are familiar, such as Dr Nikola, Dr Fu Manchu and the Four Just Men (photo by Roger Johnson)
Sherlock Holmes Society of London: But what of Madame Koluchy, Fantomas and Olga Romanoff? (photo by Roger Johnson)
Sherlock Holmes Society of London: Their criminal exploits made for immensely popular reading (photo by Roger Johnson)
Sherlock Holmes Society of London: A special favourite of Michael's is Monsieur Zenith, arch-enemy of Sexton Blake (photo by Roger Johnson)
Sherlock Holmes Society of London: And then there are the likes of Raffles and Arsène Lupin, the "gentleman crooks" (photo by Roger Johnson)
Sherlock Holmes Society of London: Less well-known criminal gentry include Colonel Clay and Simon Carne (photo by Roger Johnson)
Sherlock Holmes Society of London: There are "lady crooks" as well. Edgar Wallace, who created the Four Just Men, also chronicled the crimes of Four-Square Jane (photo by Roger Johnson)
Sherlock Holmes Society of London: Tales of the notorious Sophie Lang and Anna Brandt were widely enjoyed (photo by Roger Johnson)
Sherlock Holmes Society of London: The stories of Sherlock Holmes are as popular as ever, and many of these rival thrillers can still be read with great pleasure (photo by Roger Johnson)
Sherlock Holmes Society of London: A fascinating talk! Are there questions for Michael? (photo by Roger Johnson)
Sherlock Holmes Society of London: Jonathan McCafferty wonders what is the most improbable feature that Michael Dirda has encountered in these stories (photo by Roger Johnson)
Sherlock Holmes Society of London: The most improbable is a gruesome feature involving a corpse-double! (photo by Roger Johnson)
Sherlock Holmes Society of London: Elaine McCafferty asks how popular these tales were when they were first published (photo by Roger Johnson)
Sherlock Holmes Society of London: These stories of the rivals of Professor Moriarty were very popular indeed - and many of them deserve to be read now (photo by Roger Johnson) !