As part of a program to prepare public librarians to serve the urban disadvantaged, the faculty at Wayne State University experimented with simulation as an instructional technique. They developed and tested a library game, LIB SIM, aimed at introducing students to the relationships between main library and various branches in a large urban public library, and the ways in which community pressures and political and economic events at local, state and national levels can impinge upon library policies and services. The simulation described in this report was an effort to build upon the experience with LIB SIM and to develop a simulation simple enough to be playable within an ordinary two hour class period (including the essential de-briefing or class discussion to clarify and focus the issues raised) and realistic enough to be a genuine learning experience. The model here described focussed upon teaching students how to work as change agents within a typical library bureaucratic structure. It was tested in two sessions of a new core course at Wayne State on Issues in Librarianship required of all students in their last quarter of the curriculum. The experience with INTERACTION was positive. In addition, the model seems flexible enough to lend itself to focus on a variety of library problems. (Author/SJ)