Stephen J. Mellor is cofounder of Project Technology, Inc., a company focused on tools to execute and translate UML models, where he now serves as vice president. He chaired the UML Action Semantics Consortium, and is now active in specifying MDA. In his copious spare time, he is a member of the IEEE Software Industrial Advisory Board.
Marc J. Balcer is a consultant with fifteen years of experience in providing custom application development services to Global 1000 companies. In 1991 he began his collaboration with Stephen J. Mellor and the late Sally Shlaer, and he now applies the techniques on client projects in such diverse areas as medical instrumentation, transportation logistics, telecommunications, and financial services.