Value Stream Mapping (VSM) is a Lean management technique that visualizes the flow of materials and information required to deliver a product or service from initial request to customer delivery. Originally developed for manufacturing by Toyota, VSM has evolved into a foundational tool for DevOps, software delivery, and process improvement across industries. The core insight: most time in any process is spent waiting, not working — Flow Efficiency in typical organizations averages just 5-15%, meaning 85-95% of lead time is pure waste. VSM makes this invisible waste visible, enabling teams to identify constraints, eliminate bottlenecks, and design flow-optimized future states that dramatically reduce delivery time while improving quality.