But there is more to it than that. Unlike many mainstream novelists, crime writers are enthralled by storytelling. They are drawn to books that have beginnings, middles and ends, even though the form has now become so stylized that a reader cannot expect the three parts to be in the traditional order. Solving the puzzle is often the least important part of crime fiction, with all sorts of writers, from Ruth Rendell to Rankin to Robinson, telling us who did it to whom on the very first page. It is the why, not the how, that intrigues them and keeps us turning the pages.