To date, courses on human-computer interaction (HCI) at different institutions are very different in their content and form. They are often criticized as too practical or too theoretical, too technical or too behavioural. This paper proposes and illustrates an approach for introducing HCI that blends psychology, the work context and practical techniques. It is based on the goal of attaining a fit between user, task and technology and combines two themes that organize the material. First, user activity is examined at four levels of interaction: task, semantic, syntactic and lexical. The discussion of any specific topic, such as the use of graphics, is conducted in the task context. In this paper the context is managerial and office work, which include tasks such as making decisions and communicating. Second, user activity is analysed as a function of user characteristics such as memory, attention, comprehension and affect. The approach is demonstrated with a lesson on the design of windows.