Book excerpt: The Constructivist Credo is a set of foundational principles for those wishing to conduct social science research within the constructivist paradigm. They were distilled by Yvonna Lincoln and Egon Guba from their many writings on this topic and are provided in the form of 150 propositional statements. After Guba’s death in 2008, the Credo was completed by Lincoln and is presented here. In addition to the key principles of constructivist thought, the volume also contains an introduction to constructivism, an intellectual biography and complete bibliography of Guba’s work, and a case study using constructivism, showing how the paradigm can be applied to a research study.