Sherlock's quote in the opening is a direct quote (albeit truncated) from Arthur Conan Doyle's story, "The Sign of the Four" and is as follows (in its entirety, as originally written): "My mind rebels at stagnation. Give me problems, give me work, give me the most abstruse cryptogram or the most intricate analysis, and I am in my own proper atmosphere. I can dispense then with artificial stimulants. But I abhor the dull routine of existence. I crave for mental exaltation. That is why I have chosen my own particular profession, or rather created it, for I am the only one in the world."
This episode was broadcast on US TV two days prior to a shooting of two NYPD officers, Wenjian Liu and Rafael Ramos, in Brooklyn
A stone, as a measure of weight, is 14 pounds (about 6.35 kg), therefore a man weighing "14 stone" is about 200 lbs or 89 kg.
Ken Marks has played four different characters over the course of the series:
- Episode 3.8 End of Watch (2014) - Moderator
- Episode 2.21 The Man with the Twisted Lip (2014) - Meeting Leader
- Episode 2.7 The Marchioness (2013) - Chairman
- Episode 1.2 While You Were Sleeping (2012) - Moderator