We discuss the evolution of online help; book-oriented, exploratory, and constructive. Book oriented online help mirrors paper-based documentation; it is relatively static, linear, and is structured in a manner familiar to most users; but this type of online help is often not efficient at responding to the complex demands of specific users and tasks. Hypertext-based online help-either exploratory or constructive-offers an alternative model addressing some of the limitations of book-oriented online help. Exploratory online help takes advantage of a higher level of interactivity. It is possible to create multiple paths in a document, but it is more complex to navigate (because less familiar to users) than books. Constructive online help represents a higher level of complexity, customization, and interactivity. It can provide a higher level of feedback between users, managers, and developers. It can encourage users to reconceptualize projects and work habits but may require time to construct and gatekeep to avoid cognitive overload.