The Fourth DoorPaul Halter is France's answer to John Dickson Carr. Martin Edwards The ultimate locked room mystery. In Paul Halter's The Fourth Door, the impossible becomes reality. A haunted room. An unbroken seal. A murder victim whose very identity is an enigma. And then, a second death in a house surrounded by untrodden snow. Both crimes defy reason but master detective Dr. Alan Twist reveals that even the most baffling mysteries have rational explanations.