The term ‘psychological thriller’ is an elastic one these days, tagged liberally on to any story of suspense that explores motivations while keeping blood and chainsaws to a minimum. In many cases, the line between a thriller and a crime novel has become too blurred to be useful. In the novels of Nicci French, however, there is little ambiguity: their pattern is to deliver the mental shock-equivalent of a dead body, followed only later by a real one.