Almost all medium- and large-scale businesses rely on electronic workflow systems to manage their business processes. A key challenge is to enable the easy re-use and modification of these workflow schemas and their piece-parts, so that they can be adapted to new business situations. This paper describes an approach for automatic construction (and thus, evolution) of a workflow schema that satisfies a specified condition (or "goal"), starting from a set of basic building block services (or "tasks"). We use a workflow model based on "business artifacts", which represent key (real or conceptual) business entities, and include both the business-relevant data about them and a specification of their lifecycle, that is, how they can evolve over time as they move through the workflow as the result of services being applied to them. This paper uses a declarative form of artifact-centric workflow. The services are non-deterministic, which corresponds to the intuit...