This part of ISO 9241 provides ergonomic design principles formulated in general terms, i.e. they are presented without reference to situations of use, application, environment or technology. This standard provides a framework for applying the principles in analysis, design and evaluation of interactive systems. While this standard applies to all types of interactive systems, it does not cover the specifics of every context of use (e. g. safety critical systems, collaborative work). This International Standard serves the following types of users: - designers of user interface development tools and style guides to be used by user interface designers; - user interface designers, who will apply the guidance during the development process; - developers, who will apply the guidance during design and implementation of system functionality; - buyers, who will reference this International Standard during product procurement; - evaluators, who are responsible for ensuring that products meet the recommendations of the International Standard. This International Standard focuses on dialogue principles that are related to the ergonomic design of the dialogue between user and interactive system and do not consider any other aspects of design such as marketing, aesthetics and corporate design. The list of recommendations for each of the dialogue principles is not exhaustive.