Discuss the nature of the detective novel with reference to Wilkie Collins' Woman in White.

In many ways, the origin of the detective novel overlaps with a genre known as the "sensation" novel. This was a genre of popular writing in the Victorian period that was intensely plot driven, often relying on mystery, horror, and suspense. Unlike the Gothic novel, with its exotic locales and suggestions of the supernatural, the sensation novel, despite its lurid plots involving bigamy, murder, madness, and secret identities, was set against an ordinary background and portrayed daily life in a relatively realistic fashion. In fact, the plots of the sensation novels were often taken from major events in the news, such as the Yelverton scandal. 
Walter Hartright, the protagonist of Wilkie Collins' The Woman in White takes on the role of an amateur detective, resolving the mysteries of the past, such as the identity of the "woman in white", Sir Percival's birth, and Count Fosco's secret society, to bring the novel to a happy resolution. He acts as a viewpoint character. Suspense, as became typical in the detective novel, is generated not so much by the question of what will happen (although that is an essential part of the plot) but of the detective gradually learning and revealing to the reader what did happen in the past or the significance of events we hear about but do not fully understand. 
Most critics consider Collins' The Moonstone more of a prototypical detective novel than The Woman in White.