Why are Victorian novels so enormously long?

Because most of them were first sold in pieces. Most Victorian novels appeared not as finished books but as installments in monthly or weekly magazines, a format that took off after the wild success of Charles Dickens's The Pickwick Papers in 1836. Serialisation was one of the main reasons 19th-century novels grew so long: if a story was selling, authors and publishers simply kept it going.

The money behind it is clearest across the Channel in France, where the serial novel was called the feuilleton and authors were paid by the line and by the episode: Alexandre Dumas's The Count of Monte Cristo was stretched out to 139 installments, and a serial by Eugène Sue once pushed a newspaper's circulation from 3,600 to 25,000 copies.

That pay structure turned some writers into machines. Dumas often worked twelve to fourteen hours a day, juggling several serialised novels at once, while Wilkie Collins, credited with inventing the detective novel with The Moonstone, was never more than a week ahead of what was already being printed. Arthur Conan Doyle wrote the Sherlock Holmes stories the same way, for serialisation in The Strand magazine.

Reading was different too. Instead of sitting down with a finished book, readers often followed a serialised novel in installments over as long as a year, and authors and periodicals often responded to how the audience reacted. A rapidly growing, increasingly literate middle class gave that system its audience: education access expanded fast in the 19th century, and literacy rates climbed until they were nearly universal by its end.