A prototyping development method is presented here which has the potential to reduce the growing application development backlog. Prior research and our findings indicate that a prototyping process can assist in the efficient development of application systems by breaking a complex problem into several comprehensive parts. A state-transition model of the IS development process is presented and discussed. A two-prototype method is explained in the context of this model. Two projects are described which are typical of development efforts made by end users in a microcomputer environment and IS specialists in a mainframe environment.