This part of ISO 9241 sets forth ergonomic design principles formulated in general terms (i.e. presented without reference to situations of use, application, environment or technology) and provides a framework for applying those principles to the analysis, design and evaluation of interactive systems. While this part of ISO 9241 is applicable to all types of interactive systems, it does not cover the specifics of every context of use (e.g. safety critical systems, collaborative work). It is intended for 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 part of ISO 9241 during product procurement; — evaluators, who are responsible for ensuring that products meet its recommendations. This part of ISO 9241 focuses on dialogue principles related to the ergonomic design of the dialogue between user and interactive system, and does not consider any other aspect of design such as marketing, aesthetics or corporate design. The list of recommendations for each of the dialogue principles is not exhaustive.