Critical Path Analysis (CPA) is a tool that uses a diagram of interconnected tasks to help plan, schedule, and manage projects by identifying the longest continuous chain of tasks. It allows project managers to determine the shortest possible time needed to complete a project, recognize and resolve issues that could delay completion, and identify tasks that can be done simultaneously. CPA involves listing all project activities, diagramming them to show dependencies and parallel tasks, then analyzing the diagram to determine the critical path - the sequence of tasks that must be finished on time or the whole project will be delayed.