The author conducted a year-long study of his own fifth-grade classroom as a teacher-researcher. The intent was to create a theme study classroom, organizing curriculum around the problems, needs, and interests of students through interdisciplinary investigations of themes. Using action research, implementation processes and constraints were investigated from a teacher's perspective. An inquiry was conducted into the meanings of theme study from a teacher's perspective. He inquired into the meanings of theme study developed by students and the teacher, and explored the resulting conceptions of knowledge revealed in student actions and teacher reflection. The year began by exploring the theme "Why are we here?" The second semester themes were "exploring the unknown,""taking off on investigations," and "greed and charity." As the year progressed, students became more able to carry on an instructional conversation that moved back and forth from school study to the events in the world around them. The author's definitions of theme study evolved as the curriculum was enacted. The stance of the students toward knowledge became a primary concern as they moved from a passive relationship with knowledge to an active and communal approach. Insights from this classroom should be useful for those studying both curriculum and theory as it raises questions of the teacher's and students' relationships to knowledge. Three figures illustrate the discussion. (SLD)