How can scientists and science communicators effectively engage the public in times of crisis and in the face of pervasive uncertainty? Drawing on the experiences of the Covid-19 pandemic and the escalating climate crisis, the three essays in this volume examine key dimensions of this challenge. What roles should scientists play in policy-making? How can the spread of fake news in science communication be curtailed? And how can we represent uncertainties in a way that upholds the credibility of scientific knowledge?