The Seventh Hypothesis

The Seventh Hypothesis (La Septième Hypothèse) is a 1991 book by Paul Halter.

In 2014, The Guardian's Adrian McKinty considered The Seventh Hypothesis the third best locked-room mystery. One plot point turns on the revelation that a Mechanical Turk chess automaton was operated by a person inside the machine, reflecting a recurring theme in Halter's books that technology might allow seemingly-supernatural events to be real.