A runbook is a detailed step-by-step guide for a specific operational or emergency scenario. Examples include “perform database failover”, “mitigate DDoS attack”, or “provision new server”. Runbooks ensure that even under stress the correct steps are executed in the correct order. You should keep runbooks simple and precise so that less experienced team members can follow them. In an ISMS, runbooks are part of operational documentation and are tested and updated regularly. Automated runbooks (e.g. via Ansible) further reduce the potential for human error.