development of its Polaris missile program. While the term "work breakdown structure" was not used, this first implementation of PERT did organize the tasks into product-oriented categories.

By June 1962, DoD, NASA, and the aerospace industry published a document for the PERT/COST system, which described the WBS approach. This guide was endorsed by the Secretary of Defense for adoption by all services. In 1968, the DoD issued "Work Breakdown Structures for Defense Materiel