The document gives guidance on the design of work systems, including task and equipment design and design of the workplace, as well as working conditions, emphasizing mental workload and its effects, as specified in ISO 1075. It applies to the adequate design of work and use of human capacities with the intention to provide for optimal working conditions with respect to health and safety, well-being, performance, effectiveness, preventing over- as well as underload in order to avoid the impairing efftects described in ISO 10075. This standard does not address problems of measurement of mental workload or its effects. For the purpose of this part of ISO 10075, the definitions given in ISO 6385 and ISO 10075-1 should be applied.