Managing playback of supplemental information

A computing device may provide an interface that enables a user to playback audio content including supplemental information. The supplemental information may correspond, for example, to endnotes, footnotes, glossaries, appendices, commentary from an author, editor, or other party, or to additional supplemental information. During playback of the audio content, a user may indicate that an item of supplemental information associated with a current playback position of the audio content should be played. In some embodiments, this indication may be in response to an indication to the user that supplemental information is available. The device may then playback the supplemental information associated with the current playback position.