HarperCollins has partnered with children's app developer Loud Crow Interactive to create an app for the classic picture book Goodnight Moon. The app, which is available on iTunes for $4.99, features narration and a soundtrack, as well as over 200 items that can be tapped.

HC said Goodnight Moon, which was originally published in 1947, is one of the bestselling children's books of all time, having moved over 60 million copies. This app – it's available for iPad, iPhone and iPod Touch – will be sold alongside existing apps that are based on the book, Goodnight Moon ABC and Goodnight Moon 123.