With YAWL’s graphical editor, business processes can be modelled in a dialog between modelling experts and domain experts. The resulting models are a precise yet intuitive description of the control flow of a business process. In a second step, these models are enriched by information on data and resources required for each task. The resources can either be human participants or technical components.With the information of control flow, data and resources, the YAWL system is able to generate a complete web-based system that can instantly be used by end-users – and especially by domain experts – for executing the business processes in an interactive way. By actually logging into the system and performing the tasks of the business process, domain experts get instant feedback on their process model and make improvements gradually. When the process model is thus validated and agreed upon, the prototype workflow is a solid basis for the next steps in process automation.