The document discusses Work Breakdown Structure (WBS), which is a deliverable-oriented decomposition of a project into smaller, more manageable components. A WBS breaks down the project scope into smaller parts for estimating, scheduling, and monitoring and control. It helps define the total scope of work, assign responsibilities, and track costs, schedule, and deliverables. The key steps to develop a WBS are to identify the main project deliverables and break them down into successively smaller work packages or tasks in a hierarchical manner. This allows estimating time and costs for each component and monitoring project progress.