How is the relationship between science and policy changing in an era marked by technological disruption, media fragmentation, and political polarisation? To improve policy relevance and societal trust, science must be made more usable and socially robust. This entails co-production of knowledge with extended peer communitiesExtended peer communities that include not only experts, but also stakeholders and lay citizens. The chapter surveys methods emerging from Post Normal Science (PNS), Adaptive ManagementAdaptive Management, and Robust Decision MakingRobust Decision Making that aim to incorporate diverse perspectives, values, and types of knowledge. Case studies highlight how involving non-traditional actors in scientific assessment can increase legitimacy and local uptake of policies. Local activities like citizen juriesCitizen jury and community science are contrasted with global efforts, such as the IPCC and IPBESIntergovernmental Platform on Biodiversity and Ecosystem Services (IPBES)‘s contrasting approaches to global consensus. All approaches face major challenges of scalability and timeliness. While local, face-to-face engagements often succeed in building trust and integrating multiple perspectives, these successes are difficult to replicate at national or global levels. Advancing science-for-policy in the 21st century requires both institutional reform and cultural change. Scientists must move beyond the role of detached advisors and embrace more participatory, deliberative, and transparent forms of engagement. This includes recognising the value of local and experiential knowledge, developing tools to communicate uncertainty effectively, and rethinking how science can contribute to decision-making without demanding epistemic supremacy. In a world where AI may shape public perception as much as scientific consensus, and where populist movements undermine institutional legitimacy, building socially robust knowledge through extended communities may offer the best hope for restoring trust and navigating complexity—though the road ahead demands patience, flexibility, and humility.