Object-oriented programming is a popular buzzword these days. What is the reason for this popularity? Is object-oriented programming the solution to the software crisis or is it just a fad? Is it a simple evolutionary step or a radical change in software methodology? What is the central idea behind object-orien ted design? Are there special applications for which object-oriented program ming is particularly suited? Which object-oriented language should be used? There is no simple answer to these questions. Although object-oriented programming was invented more than twenty years ago, we still...