Co-author and instructor Tom Hathaway presents a summary of the course “Data Flow Diagrams – Simply Put”. He explains why a Data Flow Diagram is such a phenomenal tool for depicting the flow of information through an organization’s value chain. He lists the main steps of creating a Rigorous Physical Process Model, evolve it to a Context-Level Data Flow Diagram, and explode the context-level process(es) and data to reveal the nitty-gritty detail (individual process specifications and detailed data specifications) that developers need.