This paper will focus on a specific aspect of the opportunities opened up by electronic publishing on the NII -the ability to present information in multiple modalities and thereby free it from any single presentation medium. Traditional printed communication relies on a passive intermediary, paper,for the exchange of information between the author and reader. Ideas put down on paper come back to life only when perused by the reader.
Electronic publishing is mediated by a computer, an agent capable of processing the information.
Electronic information can be processed and displayed in a manner best suited to each individual's needs. AsTeR can speak both literary texts and highly technical documents that contain complex mathematics. The adequacy of the audio rendering depends on how well the electronic document captures the essential internal structure of the information. In this paper, we discuss capturing structure and give guidelines for authors to follow to ensure that their documents exhibit structure adequately. In the context of the NII, the digital libraries of the future can be viewed as large information servers that allow multiple clients to access and display information in a format chosen by the user.