They Do It with Mirrors

E-book exclusive extras:1) Christie biographer Charles Osborne's essay on They Do It with Mirrors;2) "The Marples": the complete guide to all the cases of crime literature's foremost female detective.A sense of danger pervades the rambling Victorian mansion in which Jane Marple’s friend Carrie Louise lives—and not only because the building doubles as a rehabilitation centre for criminal youths. One inmate attempts, and fails, to shoot dead the administrator. But simultaneously, in another part of the building, a my…