For the past 20 years programmers have been happy solving problems through the methods and data of classes. Though they call it object-oriented programming there are few of them who ever think in objects, and fewer who actually write objects. Even design is dominated by class diagrams, whether informally written on whiteboards or cast in UML, and nary an object diagram is ever seen. The distinctions are crucially important, as Alan Kay named object-orientation for theobjects that represent the operational models that our brains combine to solve problems. Problem-solving is about understanding a network of interacting objects. Yet with contemporary polymorphism we can’t even say much about the makeup of an object’s neighbor (by design!), let alone what it’s going to do when we send it a message. The trygve programming language strives to restore a more fully object-oriented mindset by expressing how processing flows through a network of cooperating objects. You can read these flows in the source code, which means that you can reason about use cases and system state in an object world, rather than focus on isolated object state in a class world. Thus, trygve programs can more fully express the business mental models that we deliver for value in use cases. Code that is understandable is less likely to have bugs and is more likely to be maintainable than code whose distribution across classes defies comprehension.