The_Black_Spectacles
The Black Spectacles
1939 novel by John Dickson Carr
The Black Spectacles (published in the US as The Problem of the Green Capsule, with the subtitle "Being the psychologist's murder case"), first published in 1939, is a detective story by John Dickson Carr featuring his series detective Gideon Fell. This novel is a mystery of the type known as a locked room mystery (or more properly a subset of the locked room mystery called an "impossible crime" story).