Successful multivariable control system design demands knowledge, skill and creativity of the designer. Artificial intelligence can facilitate the design process by capturing much of the knowledge and some of the skill of the designer into an intelligent design tool, leaving the designer free to concentrate more on the creativity aspect of the design. This publication investigates the contribution which artificial intelligence can make to multivariable control system design. It covers all the research, design, development and testing aspects of creating the expert system. The approach is a critical one, reporting on the success as well as the shortcomings of expert system technology. Full documentation of the design software applications relevant to new and experienced users is given.