The elements of Christie’s fiction are all already in place: a country house, a finite list of suspects, the outsider detective intruding into a place of order and hierarchy that has been disrupted by a crime. The world of Christie’s books is something like the ‘imaginary’ as described by Cornelius Castoriadis, a mental representation in which this orderly household stands for a whole society as a shared universe of meaning, with values and social roles encoded everywhere we look – and then, into this world comes a murder, and a detective trying to solve the murder. Something doesn’t mean what we thought it meant; someone isn’t who they appear to be; something didn’t happen the way it was said to have happened.
The Case of Agatha Christie, LRB