Today the crime novelist has one advantage denied to writers of 'straight' or 'literary' novels. Unlike them he can range over all levels of society, for crime can easily breach the barriers that exist in our stratified society. Because of these barriers the modern literary novel, unlike its 19th-century predecessors, is often confined to the horizontal, dealing only with one class. But crime runs through society from top to bottom, and so the crime novelist can present a fuller picture of the way we live now.