The problem of achieving sustainable cities is not merely one of technology transfer. Rather, it is a much more involved process of institutional change. A key sequence in city decisions is the process by which city institutional tissue gets formed, achieves a self-conscious identity, is accepted as valuable and endorsed by the broad community, and takes on the policy and practical tasks of achieving sustainable development. A decade of research and analytical work in academic and development agencies has begun to reveal the importance of collective modalities –for university researchers, venture capitalists, innovators, regions, and cities–as a strategy in achieving learning entities. The paper reviews empirical data about city learning drawn from both developed and developing countries and presents a typology to describe common modalities of city learning. (2006).