The document discusses how project managers can prepare for unexpected issues on projects. It recommends that project managers build contingency into project schedules by adding buffer time or overestimating durations. It also suggests keeping additional resources available and creating a "playbook" of plans for how to handle potential problems like delays or defects. Reviewing past project histories can help identify common issues and better ready managers for the unexpected. Preparing for uncertainties in these ways helps ensure projects can still succeed even when unforeseen obstacles occur.