Mary Poppendieck (b. 1941), together with her husband Tom Poppendieck, is the primary architect of Lean Software Development — the explicit application of Toyota Production System principles to software engineering. Their book "Lean Software Development: An Agile Toolkit" (2003) directly traces the lineage from Deming through Toyota to software, making the Poppendiecks the critical bridge between manufacturing lean and the agile-movement. Mary's background in manufacturing (she managed a government IT project and a manufacturing plant) gave her direct experience with both Deming's methods and their Toyota adaptation. The Poppendiecks identified seven wastes of software development analogous to Ohno's seven wastes, and mapped Deming's pdsa-cycle-plan-do-study-act to iterative development. Their work made explicit what was implicit in many Agile practices — that the intellectual roots trace back through toyota-production-system to Deming's system-of-profound-knowledge. Link to taiichi-ohno, lean-manufacturing, james-womack.