This paper presents a case study of a collaboration between the St. Louis (Missouri) Public Schools and Maryville University (Missouri) to develop an early childhood magnet center and professional development school (PDS), the Wilkinson Early Childhood Magnet School. This school serves a diverse population of children from age 3 through second grade. The purpose of the magnet school/PDS is to provide an exemplary education for students and their families; to function as a center for inservice and preservice teacher development; and to inquire into curriculum and practice appropriate for children in the school's age range. Strategies to develop exemplary practice have focused on developing and implementing a constructivist curriculum. Successes that have been achieved can be attributed largely to the sense of shared ownership among school and university staff. Obstacles to implementation have come from a variety of sources, including resistance to the constructivist approach from teachers and conflict between the constructivist curriculum and assessment framework and the requirements and policies of the school district. Shared decision making has produced both ownership, and thus support, of the program, as well as strains on personal relationships and staff schedules. Communication has been the greatest challenge to the collaboration. Although efforts are being made to advance institutionalization of the PDS concept, obstacles from the state, district, university, and school must be overcome. (IAH)