This chapter discusses theory, design, and analysis of the knowledge building model developed by Scardamalia and Bereiter. Knowledge building, supported by Knowledge Forum¯ examines how participants advance the state of knowledge in their community, with the creation of new knowledge as a social product. This chapter provides an overview of the history and key ideas of knowledge building; discusses principle-based pedagogy and design considerations; and examines the analysis of knowledge-building discourse including the development of analytic approaches and tools. Theory, design and analysis are integral to each other – principle-based pedagogy is to mirror and instantiate the knowledge-creation processes, and evolving classroom designs in turn enrich analytic approaches and theory development. This chapter also discusses how the knowledge-building model is related to other approaches, highlighting implications for the learning sciences pertaining to theories of knowledge creation, guided instruction versus emergent design, and new directions for learning analytics.