In the short story Mr Eastwood's Adventure, Anthony Eastwood is a writer of crime thrillers. At the beginning of the story he is attempting to write a story which he had decided to call "The Mystery of the Second Cucumber" but he is suffering from writer's block and can get no further than the title.
His deliberations are interrupted by a phone call from a stranger, a girl named Carmen. She tells him it is a matter of life and death and wants to meet at 320 Kirk Street and to use the codeword "cucumber". Anthony is intrigued by the coincidence and proceeds to the rendezvous which turns out to be a shop selling second hand glassware. Details of what happened next can be found here.
In the end it turns out that Anthony became the victim of an elaborate hoax and robbery executed by The Patterson gang. Anthony ends up losing his valuable collection of silver and enamel ware. However, all is not lost as Anthony's writer's block is cured.
Anthony's address is 48 Brandenburg Mansions and his telephone number is Northwestern 1743.