Kanban is a lean methodology for managing workflow. It uses visual cues like boards and cards to limit work in progress and optimize flow. The document discusses Kanban principles of starting with your current process and evolving it, as well as practices like visualizing work, limiting work in progress, measuring and managing flow, making policies explicit, and collaborating to improve. Examples of Kanban boards and metrics like cumulative flow diagrams are provided to illustrate Kanban concepts and techniques.