This Guide suggests how the Health Cluster lead agency, coordinator and partners can work together during a humanitarian crisis to achieve the aims of reducing avoidable mortality, morbidity and disability, and restoring the delivery of and equitable access to preventive and curative healthcare as quickly as possible. It highlights key principles of humanitarian health action and how coordination and joint efforts among health sector actors working in partner-ship can increase the effectiveness and efficiency of health interventions. It draws on IASC and other documents but also includes lessons from field experience.