If there are a lot of tasks on the project and/or the tasks need to be organized by deliverables, billables, milestones, phases or grouped just for easier navigation then Summary tasks can be used. Summary tasks enables grouping of tasks by setting a main task (the summary task) and then adding child or detailed tasks below it. All the information from child tasks roll up automatically to give totals at the summary task level. Child and summary tasks can be nested multiple levels deep if required. Summary tasks are also used to optimize performance. Collapse the display of all tasks in summary tasks, so only those child tasks in a specific section are visible. For more information see Summary Tasks.