Graphs can be used to convey information about relationships in many applications. State transition diagrams, PERT/CPM charts, and entity-relationship diagrams are a few examples of many applications involving graphs. Typically, nodes in the graph represent items in the application and the edges represent the relationships among these items. A graph editor is an interactive tool that presents a graph to the user pictorially and allows the user to edit the graph. This monograph presents the design of an extendible graph editor, which is a graph editor that can be adapted easily to many...