Ergonomics is defined as the study of efficiency of persons in their working environment, and is a fast developing applied science. A considerable amount of information has emerged during the last five years and this updated edition will be directed towards those who wish to learn about the importance of designing the environment with the human operator in mind. The structure and thematic approach of this edition remains similar to the previous editions - thus the emphasis will be on helping the student to develop an understanding of ergonomics through the concept of the flow of information between man and machine in the system and the extent to which different aspects of the system may help or hinder this information flow.