AbstractThis is the second part of a report which looks at expert systems and the man‐machine interface (mmi). The term ‘mmi’ is interpreted in a fairly broad sense to include knowledge acquisition and cognitive aspects of the user interface. Part One of the report (published in the previous issue of Expert Systems) examines what is currently happening in the area of knowledge acquisition in Britain and asks whether it really is the major bottleneck in the production of expert systems.Part Two of the report looks at cognitive aspects of the user interface, including dialogue control, explanation facilities, user models, natural language processing and the effects of new technology. It also considers the very important question of evaluation. Again the report is concerned with what is actually happening in these areas in Britain