The contributors to this volume utilize a variety of examples – ecologically-sensitive, regional planning in Naples (Italy); congestion pricing in New York City; and public participation in Europe, among others – to explore how planners engage a heterogeneous and restless world. Inspired by assemblage thinking and actor-network theory, each chapter draws on this "new materialism" to acknowledge, in quite pragmatic ways, that spatial politics is a process of becoming that is inseparable from the materiality of urban practices.