The ITS architecture separates applications into four layers. The action layer implements back-end application functions. The dialog layer defines the content of the user interface, independent of its style. Content specifies the objects included in each frame of the interface, the flow of control among frames, and what actions are associated with each object. The style rule layer defines the presentation and behavior of a family of interaction techniques. Finally, the style program layer implements primitive toolkit objects that are composed by the rule layer into complete interaction techniques. This paper describes the architecture in detail, compares it with previous User Interface Management systems and toolkits, and describes how ITS is being used to implement the visitor information system for EXPO '92. © 1990, ACM. All rights reserved.