An UNDAC mission normally follows a typical operational cycle, covering three interrelated phases of activity: pre-mission, on-mission and post-mission. Awareness of the mission cycle and of the required actions per phase will help UNDAC members anticipate and plan operational activities in the field. This chapter provides detailed information on each stage of the mission cycle, including actions to be taken by individual members, by the Team Leader, UNDAC as a team, and OCHA ERS. A comprehensive checklist can be found in the short version of the UNDAC Handbook.