Which Dickens novel was left unfinished at his death?

The Dickens novel left unfinished at his death was The Mystery of Edwin Drood. It was his final novel, and Charles Dickens died before he could reveal how its central disappearance and suspected murder would be resolved.

Dickens began publishing the novel in monthly instalments in 1870, with illustrations by Luke Fildes. The planned story was shorter than many of his earlier serial novels: twelve instalments were scheduled, but only six were completed before Dickens died on 9 June 1870. The surviving text ends with Edwin Drood missing and suspicion falling on several characters.

The unfinished ending has made the book a literary mystery as well as a mystery novel. John Jasper, Edwin's uncle and a cathedral choirmaster, is widely suspected of murdering him, partly because Dickens reportedly described the intended plot to his friend John Forster. However, Dickens left no complete, authoritative solution, so later writers produced continuations and adaptations. Little Dorrit, Dombey and Son, and Our Mutual Friend were all completed and published during Dickens's lifetime.