Abstract : This thesis focuses on the software engineering design and implementation of Human- Computer Interfaces. We concentrate on multifeature systems which integrate new techniques as multiple communication means. We examine user, as well as system activities. We therefore assign various steps in the abstraction and concretisation mechanisms for information exchange between the user and the system. The Pipe-lines design space organises these steps within a framework that integrates both user and system activities. On the basis of Pipe-lines we develop a classification scheme which helps evaluating the usability of such systems: The UOM scheme (Usage, Option and Multiplicity). A software engineering perspective based on Pipe-lines is then adopted: To do so we identified software requirements from Pipe-lines for defining the PAC-Amodeus software architecture model. The exploitation of PAC-Amodeus urged us to develop a methodology expressed as a set of heuristic rules that helps defining the software agents. These rules led to the development of a software engineering tool - an expert system called PAC-Expert. In relation to PAC-Amodeus, a mechanism is provided that combines information specified by the user through different input devices and interaction languages. The fusion mechanism is domain-independent and forms the structural skeleton upon which multifeature systems can be built.