Diagrams are everywhere, especially in complex systems. We use diagrams to reason, to communicate vision, and to navigate complex decisions. People often use them in private spaces such as notebooks, in public spaces such as whiteboards, and spaces in-between like technical documentation. At the same time, they've neglected ever seeing a professional diagramming course. Wouldn't it be good if we could make diagrams a little bit better? In this session, you will explore how diagrams have aided the development of complex systems. You will learn what we can do today to make more effective diagrams. You’ll also gain some ideas as to how to support others in creating expressive, engaging, clear diagrams in a variety of agile contexts. We'll also look at some of the latest diagramming theory from research, and will apply this to organizational and tech architecture diagrams.