1. One or more computer storage media having stored thereon multiple instructions that, when executed by one or more processors of a device, cause the one or more processors to: display, in each of two display areas, different pages of a digital book using a book display model; display, in response to a request to semantically zoom out, the digital book in a broader context, the broader context using a context display model rather than the book display model; and display, in response to a request to semantically zoom in, the digital book in the book display model rather than the context display model.