A problem domain analysis is described employing a method recently developed and applied at the Warton Unit of the Military Aircraft Division of British Aerospace. The method is based on the definition of attributes of a software component which categorise the component as re-usable, re-usable with modification or non-re-usable. These attributes were presented to a domain specialist in the form of a structured questionnaire. This work is the first stage in discovering ways to design a re-usable software component. Also detailed are the stages involved in the re-design of one of the re-usable components to enhance its re-usability, and an evaluation of the University of Strathclyde's intelligent knowledge-based cataloguing system is given. Finally, further work towards the development of a re-use support system is summarised.