An exploratory investigation attempted to determine how learning at work actually takes place and in what ways learning on the job differs from classroom learning. The study was based on extensive observations and interviews over a 5-year period at two manufacturing plants that implemented a computer-based system known as Manufacturing Resource Planning (MRP). (MRP is both a computer system and a theory of manufacturing, designed to integrate information from all aspects of a company's operations to guide employees making production and inventory decisions.) The occupation of planner was selected for the core study since a planner within an MRP environment uses the system in relation to everyday production knowledge. Three knowledge domains were identified: MRP as a theoretical system, practical production knowledge, and functional production knowledge. The study found the following: (1) daily, everyday work activities are settings for learning; (2) without extensive academic, professional, or even on-the-job training, people can achieve conceptual understanding on the job; (3) how the workplace is set up, not the presence of technology, enhances or inhibits learning; and (4) because people come to their jobs from a large variety of routes, educational planners need to consider providing multiple and alternative educational forms as being as important as trying to design the one best training program. The study concluded that the workplace clearly is a learning environment and that people can learn formal concepts through work, not only in the classroom. (KC)