Starting in the 1940s and continuing to the present, the Japanese automotive industry, led by Toyota, created a new method of manufacturing based on a demand-driven, or “pull,” model. In this model inventory is not stored in large warehouses or parking lots but supplied when a new car or product is ordered by downstream consumers. This method is contrasted with the traditional, or “push,” method of manufacturing where products are constructed on an assembly line without regard for the upstream demand by the end user or consumer. A pull model, in contrast, depends on accurate and timely metrics about what materials or services are necessary to deliver the end product with minimal wastage in the manufacturing workflow. The lean startup model presented in this book uses this emphasis on “pull” to accurately test and generate metrics on the effectiveness of a library’s technology and organization.