Is that a phone book in your pocket, darling?

When Nick Cave wrote The Death of Bunny Munro, he and his British publisher, Canongate Books, worked with a multimedia company to develop an app for the iPhone that included not just the novel but also videos, music composed by Cave, and audio of the author reading the book.

"What you can do with graphics and moving images creates a lot of possibilities for a publisher that have never existed before," Canongate's Jamie Byng told The Scotsman.

Publishers are now rushing to develop new forms of books for readers who want to see them on smartphones. One out of every five new applications introduced for the iPhone last month was a book, according to Flurry, a research firm that studies mobile trends. Companies like EnhancedEditions, BeamItDown and ScrollMotion, which create and sell books in the form of applications, are suddenly doing good business.

Over the last eight months, Amazon and a number of smaller companies have released book-reading software for the iPhone and other mobile devices. People who want to read electronic books are discovering that they can do so on the smartphones already in their pockets, which gives "phone book" a whole new meaning.