It is generally agreed that there is a need for strong pedagogical principles to inform course design, particularly when there is any major investment in the production of resource-based learning (RBL) and computer-aided learning (CAL) materials. Such principles should also take into account the special challenges posed by hypertext environments. In this paper, there is a summary of principles of course design as exemplified and realised in CASTE (Course Assembly System and Tutorial Environment). CASTE was developed by Pask and Scott [18] in response to the need to share with learners a description of a body of subject matter, such that there could be “conversation” between system and student about learning strategies. Whalley [27] refers to CASTE as a system that “provided both a ‘virtual’ environment for the student and a system to facilitate learning conversations about it” and “clearly worked as an integrated whole”. In CASTE, there are well-justified principles which deal with the creation and deployment of the following: learning outcomes; advance organisers; analysis of course content as a coherent, consistent, learnable whole; tutorial strategies; use of activities; formative assessment; using learning contracts for mastery; summative assessment by “teachback”. There are overlaps with other approaches to instructional design (e.g., [7,21,26]. It is argued that the CASTE principles provide a more coherent theoretical framework, a simpler taxonomy of learning processes and simpler terminology.