The quick start overview has attempted to demonstrate how a few key planning variables can produce what appears to be a coherent plan. This chapter describes how work packages (WPs) were the building blocks to form the project Work Breakdown Structure and through these the overall project work and deliverable scope is defined. From a work definition perspective, the WP becomes a management focus point for both planning and control activities. The most visible outcome of examining the internals of a defined WP is to see that it initially contains estimates for the required resources to execute the work, estimated duration, cost, and linkages to other work tasks. If the project management can keep the defined WP variables in line this set of mechanics is an important project management step and represents an important artifact that serves as a useful tool to communicate goals and status among the various project stakeholders.