Use case modeling has become a very popular object-oriented analysis technique, since Jacobson first published his ideas on the subject nearly seven years ago. The "non-technical" nature of use cases allows users to participate in a way that is seldom possible using the abstractions of object modeling alone. Use cases help the analyst get a grip on specific user needs before analyzing the internal mechanics of a system, providing a basis for early prototyping and a means of driving units for incremental delivery.