The Woman in White by Wilkie Collins was published in 1859, and is often considered one of the earliest mystery or detective novels, although it is also classified as a "sensation novel". It shared in common with other sensation novels a dramatic, suspense-filled plot, including murder, false identities, insanity, and illegitimacy.
The protagonist of the novel, Walter Hartright, is an artist who has found a job as a drawing master to the two young women at Limmeridge House in Cumberland. Before leaving for his new post, he talks with the mysterious "woman in white" of the title, discovers that she is acquainted with his new employers, and realizes that the police are searching for her.
At Limmeridge, Walter falls in love with the beautiful Laura Fairlie and discovers that the woman in white must have been Anne Catherick, daughter of a family servant, who looks very much like Laura (really being her half-sister). Laura's father, on his deathbed, had requested that Laura marry Sir Percival Glyde, and Laura complies. Walter leaves for several months. During this period the evil Sir Percival and his accomplice, the equally evil Count Fosco, try to persuade Laura to sign over her inheritance to them. She refuses.
Sir Percival imprisons Laura in an insane asylum under Anne's identity. Anne dies of natural causes and Sir Percival buries Anne under Laura's identity. Walter, returning from Argentina, with the help of Laura's sister Marian, frees Laura and helps her resume her rightful identity. Sir Percival dies in a fire and the evil Count is murdered by a secret society he had betrayed. Walter and Laura marry happily.