In this Chapter, we provide an informal yet precise characterization of open declarative interaction models along different dimensions, namely modeling abstractions, time, compliance, degree of flexibility and degree of openness. We then give an overview of several application domains in which interaction plays a central role: Business Process Management (BPM), Service Oriented Computing (SOC), Clinical Guidelines (CGs) and Multi-Agent Systems (MASs). We discuss the drawbacks of procedural and closed approaches when dealing with such settings, motivating why we claim that they should be complemented with an
perspective. Finally, we describe a generic framework for managing the life cycle of open declarative interaction models, spanning from their design to their execution, monitoring and a-posteriori verification, and propose how to fill its building blocks.