Book excerpt: Bringing together contributors from Europe, North America and Australia, this book questions the purpose and outcomes of speculation in practical settings. In the context of interrelated and complex global challenges, speculation is not just useful but necessary. The chapters in this book present a cross-disciplinary dialogue of people that are developing work in speculation and interrogates its practices and ethical and political charges. Through these discussions, the book explores the potential of speculation in addressing issues such as climate change, urban futures and new political practices.