Résumé : The Web is creating exciting new possibilities for direct and instantaneous publishing of information. However, the apparent ease with which one can publish documents on the Web hides more complex issues such updating and maintaining Web pages. We believe one of the crucial requirements to document delivery is the ability to extract and reuse information from other documents or sources. In this paper we present a descriptive language that allows users to write virtual documents, where dynamic information can be retrieved from various sources, transformed, and included along with static information in HTML documents. The language uses a tree-like structure for the representation of information, and defines a database-like query language for extracting and combining information without a complete knowledge of the structure or the types of information. The data structures and the syntax of the language are presented along with examples.