Stream Reasoning refers to inference approaches and deduction mechanisms which are concerned with providing continuous inference capabilities over dynamic data. The paradigm shift from current batch-like approaches towards timely and scalable stream reasoning leverages the natural temporal order in data streams and applies windows-based processing to complex deduction tasks that go beyond continuous query processing such as those involving preferential reasoning, constraint ptimization, planning, uncertainty, non-monotonicity, non-determinism, and solution enumeration.