When I began my return to the world of computer software in 1986, objects were clearly heating up as a topic, although many developers and their managers then looked askance at what might have seemed like just another trend de jour whose 15 minutes of fame would soon fade. However, it seemed to me that there was more to the story, that objects represented another cornerstone in the foundations of software engineering practice (see Chapter 24). Encouraged by George Schussel of Digital Consulting, Inc., I organized and chaired the Object-Oriented Systems Symposium, a traveling forum that, over several successful years, provided a platform for such leaders and thinkers as Grady Booch, Dave Thomas, and Rebecca Wirfs-Brock.

Skeptics and holdouts remain, as they always will, but the revolution is largely over; object-orientation has become the dominant approach to software design and development. Every revolution seems to generate its own orthodoxy, however, and object-orientation is no exception. The revolutionary guards of the new paradigm became quick to condemn anything tainted with traces of the discarded and discredited paradigm of procedural programming, and that included use cases. Now that they are ubiquitous, it seems hard to believe that use cases were ever considered heretical (Lockwood and Constantine 1993), but many among the old and new converts to the object paradigm condemned them as counterrevolutionary. Both revolution and counterrevolution eventually succumbed to pragmatics, however, and most object-oriented methods, including the much touted Unified Process (Jacobson et al. 2000; Kruchten 2000), eventually embraced some form of use case modeling.

These two central themes of modern software engineering practice, use cases and objects, are closely linked to the theme introduced in the previous section—usability. Both objects and use cases have been applied—sometimes with elegance, sometimes with ineptitude—to the design of user interfaces. Both have, at one time or another, been trumpeted as the answer to the usability question. Both have been misunderstood and misapplied almost as often as they have been used with success. In a series of closely related articles originally written for Object Magazine, this section examines that complex intersection of software objects and use cases with user interface design and software usability. The reader whose interest is piqued by this outline will find the ideas developed more fully in Software for Use (Constantine and Lockwood 1999).