Properties of high-tech materials are highly influenced by transient processing conditions. A thorough understanding of their structural evolution during fabrication thus allows tailoring performance for specific purposes. However, many dynamic processes, such as crack propagation in composites, bubble formation in metal foams, dendrite growth during solidification, etc., occur within opaque materials usually hosted in complex conditioning environments on microscopic length scales and sub-second time scales, making them elusive to common characterization methods. To overcome these limitations, the latest developments in time-resolved synchrotron microtomography have pushed the routinely achievable time resolution well into the sub-second regime, reaching up to hundreds of tomographies per second for selected material systems, while allowing for ever more complex environments to produce realistic sample conditions. With the development of advanced tomographic reconstruction algorithms, even a live preview of virtual slices through 3D volumes in nearly real time is possible.