The problem of computerized question-answering is discussed in this paper from the point of view of certain technical, although elementary, notions of logic. Although the work reported herein has general application to the design of information systems, it is specifically motivated by the RAND Relational Data File. This system, for which a prototype has been implemented, deals with the retrieval and processing of information from a large file of relational sentences. The report does not discuss specific details of the system but rather an abstract version of it. The purpose is to demonstrate how notions in logic can be used to influence the design of components of an information system. A secondary purpose is to show how logic can be applied to the analysis of natural language. (Author)