Alfred T. Lee has been involved in the conduct of research in human-systems integration for more than 40 years. His principal research focus has been developing an understanding of how human capabilities and limitations affect the way in which complex systems function. This understanding can be used to develop designs that maximize the influence of those attributes of the human operator that can enhance the efficacy of system operation while minimizing the influence of those aspects that do not. This is particularly important for system safety as designs that do not properly integrate the human operator inevitably reduce operational safety.