The main purpose of this manual is to familiarize new UN mediators with the range of skills used by their predecessors to carry out third-party mediation. The manual describes the current context in which UN mediation and “good offices” is carried out, offers advice and lessons from previous representatives and envoys, and suggests how the UN’s Mediation Support Unit can help to support the work of UN mediators. The manual is based on the UNITAR Programme for Briefing and Debriefing Special and Personal Representatives of the Secretary-General, which involved extensive interviews with UN representatives and envoys to determine lessons learned and best practices from their work.