Gatekeeping is one of the media's central roles in public life: People rely on mediators to transform information about billions of events into a manageable number of media messages. This process determines not only which information is selected, but also what the content and nature of messages, such as news, will be. Gatekeeping Theory describes the powerful process through which events are covered by the mass media, explaining how and why certain information either passes through gates or is closed off from media attention. This book is essential for understanding how even single, seemingly trivial gatekeeping decisions can come together to shape an audience's view of the world, and illustrates what is at stake in the process.