Bright future ahead for crystallography Macromolecular x-ray crystallography typically provides static snapshots of systems at equilibrium. Advances in time-resolved crystallography have made it possible to capture dynamics in biomolecules: large and small, fast and slow. Brändén and Neutze review techniques and concepts that have emerged from recent work at x-ray free electron laser sources and are now being applied in other settings and to a growing number of biological systems. Despite challenges in analyzing and relating these data to a biological context, experiments in this field have opened new frontiers in temporal and spatial resolution and yielded many new insights into nonequilibrium chemistry and conformational changes in biology. —MAF