The article proposes and justifies a trial classification scheme. An earlier version was used to organize the papers submitted to this symposium, and the scheme has been refined somewhat in response to inadequacies discovered during the process of selecting the program. The first issue to be tackled is the heterogeneity of the topics usually considered part of requirements engineering. They include: tasks that must be completed; problems that must be solved; solutions to problems; ways of contributing to knowledge; and types of system. There seems to be a need for several orthogonal dimensions of classification. While multiple dimensions certainly help us cope with the heterogeneity of concerns, there is a danger of making the classification scheme too complex to use. I have compromised by settling on two dimensions.