The objective of this paper is to provide a balanced assessment of international cooperation among financial regulators, with a focus on banking supervision. While recognizing the undeniable -- and even unexpected -- achievements of these regulators in building a cooperative framework for financial supervision, we also suggest that this remains a work in progress, given the contemporary financial risk environment. Briefly, we argue that this environment -- to the extent we understand it, for it remains opaque in important respects -- has an almost paradoxical quality, in that risk has become both more consolidated and more atomized at the same time. On the one hand, large and complex financial institutions (LCFIs) which may be "too big to fail", increasingly dominate the banking landscape; on the other, these same institutions have shifted at least a portion of their risks onto other firms and households, whose absorptive capacity has yet to be severely tested. It is the effectiveness of the international supervisory architecture in the face of this risk environment that we consider, and we then provide some suggestions for future policy reforms.