Mark Haddon's "The Curious Incident of the Dog in the Night-Time", the first novel to be published simultaneously for the UK adult and children's market, exemplifies the phenomenon of crossover literature better perhaps than the "Harry Potter" series, whose appeal to a dual-aged audience had caught the publishing industry by surprise. This article identifies Haddon's engagement with the genre of detective fiction as one of the reasons for the novel's crossover success: while the mystery plot offers a compelling narrative "hook" for children and adults alike, the postmodern twists on the detective formula open up deeper levels of satisfaction, without alienating the less experienced members of the audience. Analysed within the context of contemporary crime fiction, "Curious Incident" also appears to be tapping into a relatively recent literary trend that sees detective novels focusing on young characters as victims, witnesses and even perpetrators of crimes--itself a reflection of our changing attitudes towards the Romantic view of childhood as an age of innocence.