A two volume guide to object-oriented programming that presents the smalltalk system as a powerful and efficient prototyping and development environment. Volume two describes the Smalltalk classes that provide the familiar overlapping windows, pop-up menus, and mouse interaction facility that characterizes the Smalltalk user interface. It also covers the model-view controller framework for the construction of user interfaces. It features the model view-controller paradigm for window-based applications, and details individual classes, including relationships between related classes and design rationales. The book is written to be used in parallel with the Smalltalk system.