This document presents a discussion of the development of a set of software tools to assist in the construction of interfaces to simulations and real-time systems. Presuppositions to the approach to interface design that was used are surveyed, the tools are described, and the conclusions drawn from these experiences in graphical interface design are discussed. Detailed descriptions of the following tools, which have been used extensively in the development of an interactive inspectable simulation-based instructional system, Steamer, are presented: (1) simulation environment; (2) model control; (3) graphics editor; (4) icon editor; and (5) knowledge-base editors, including a knowledge-editor and grapher, lesson editor, behavior editor, and designer. Numerous graphic illustrations are provided; references and a distribution list are also included. (KM)