The method described here draws upon twenty years of experience of YOURDON, Inc., whose business has been applying, adapting, and enhancing system development techniques. This intuitive, model-driven approach to systems development is suitable for both the business information and real-time engineering communities. YOURDON Systems Method (YSM) 3.0 has guided thousands of project teams and individuals, helping them meet tight project deadlines while satisfying user requirements and delivering successful solutions within budget.