EMERGO is a methodology and toolkit that supports the production and delivery of authentic scenario-based learning cases. The methodology allows teachers to create realistic problem contexts where learners take on roles and experience the consequences of their actions. The open source EMERGO toolkit uses loosely coupled components, XML data, and a scripting system to enable reusable, adaptable scenarios that can be personalized based on learner progress. It also supports features like multimedia, cooperation between learners, and real-time monitoring by tutors.