This book provides a consolidated survey of the established but scattered insights into the provision of deeply technical expertise in policy making: models of climate or disease, risk, Artificial Intelligence and ethics amongst others. It goes on to link this to emerging ideas about futures thinking, public engagement, narrative, and the role of values and sentiment alongside the place of scientific and scholarly insights in public decision-making and debate. The book offers an accessible overview aimed at practitioners, policy-makers looking to understand how to work with researchers, researchers looking to work with policy-makers, and the increasing numbers and types of “brokers” - people working at the interface, in science advice, public engagement and communication of science, and in expert support to decision-making in the public and private sectors.