This International Standard defines requirements and provides recommendations to publishers, software developers, content providers, and hardware manufacturers for the data structure, usability requirements, playback systems and delivery systems for audiobooks in digital file format. It should be noted that throughout this International Standard, the term audiobook is defined as any audio file or collection of audio files of primarily spoken word content that are played in a linear or specified order. Therefore, spoken word audio with occasional music, a narration of newspaper articles, or other similar spoken word audio is assimilated to audiobooks in this standard.