Design Principles for Interactive Software : Springer : 9780412724701 : 0412724707 : 30 Jun 1996 : IFIP's Working Group 2.7(13.4)* has, since its establishment in 1974, con­ centrated on the software problems of user interfaces. From its original interest in operating systems interfaces the group has gradually shifted em­ phasis towards the development of interactive systems. The group has orga­ nized a number of international working conferences on interactive software technology, the proceedings of which have contributed to the accumulated knowledge in the field. The current title of the Working Group is 'User Interface Engineering', with the aim of investigating the nature, concepts, and construction of user interfaces for software systems. The scope of work involved is: - to increase understanding of the development of interactive systems; - to provide a framework for reasoning about interactive systems; - to provide engineering models for their development. This report addresses a