If the reforms currently transforming public education are to be sustained, it is commonly believed that they must be founded in new conceptions of schooling. Compelling among them is the recurrent edict that teachers and other educators must learn to work together in ways heretofore considered to be discretionary and, consequently, largely a matter of personal and professional preference. Notwithstanding its rising recognition as an essential ingredient of successful schools, collaborative practice remains an erratic and elusive enterprise that is fraught with uncertainty. The literature and the authors' own research experiences are used to explore how and why the wide-scale establishment and nurturance of so-called professional learning communities may continue to evade realization. Despite habitual rhetoric to the contrary, a fundamental problem may be a lack of evidence that there is strong and manifested valuing of teacher collaborative practice as an integral component of schools as morally bound communities.