This book describes and evaluates existing models of human performance and their use in the design and evaluation of new human-technology systems. Its primary focus is on the modeling of system operators who perform supervisory and manual control tasks. After an introduction on human performance modeling, the book describes information processing, control theory, task network, and knowledge-based models. It explains models of human performance in aircraft operations, nuclear power plant control, maintenance, and the supervisory control of process control systems, such as oil refineries. The book concludes with a discussion of model parameterization and validation and recommends a number of lines of research needed to strengthen model development and application.