The Cycle of Inquiry (COI) is a tool for emergent curriculum planning and for professional development of early childhood teachers and teacher education students. The COI includes a sequence of five organizational forms connecting analysis of documentation data with intentional planning for long-term emergent inquiry inspired by the Reggio Emilia Approach. The authors discuss and analyze the COI System through examination and analysis of the work of a student in a university early childhood teacher preparation program. Through this case study, the authors explore (1) whether a preservice teacher can learn to use the COI form-driven process to plan and facilitate emergent curriculum and (2) whether a mentor can scaffold and assess the development of an inservice or preservice teacher using the teacher’s COI documentation. The authors also describe ongoing research into use of the COI System and outline potential directions for future research.