ClassAct provides object-oriented building blocks for your application in the form of Intuition BOOPSI classes available as either shared run-time or link-time libraries. As they are standard classes, they may be used with any application environment supporting BOOPSI. ClassAct is a complete GUI system in its own right, supporting everything from simple buttons to an advanced list management class, and includes a complete GUI layout system class that lets you create font-sensitive and resizable interfaces quickly and easily.