Abstract. This paper presents an experiment of parallel knowledge base development by subject matter experts, performed as part of the DARPA’s Rapid Knowledge Formation Program. It introduces the Disciple-RKF development environment used in this experiment and proposes design guidelines for systems that support authoring of problem solving knowledge by subject matter experts. Finally, it compares Disciple-RKF with the other development environments from the same DARPA program, providing further support for the proposed guidelines.