Multimedia educational software is often a glitzy version of old technology. Some educational software has become better as developers began to ask, "In what ways can the computer facilitate learning, that were not possible before?" One answer to this question is: provide a simulated environment for the learner to interact with. For multimedia to have an impact on learning, a similar question must be asked: "In what ways can multimedia facilitate learning, that were not possible before?" One answer is the Case-Based Learn-by-doing Environments (CaBLE). The computer provides a simulated environment that allows the student to learn a task by doing a task. Multimedia stories and information help connect what the learner is doing in the simulated world with events in the real world. The CaBLE tutor utilizes the following components: task simulator; interface; library of failures which can occur in the domain; library of learner mistakes; learner state map; network of declarative knowledge; and library of stories. (Contains 21 references.) (Author)