In-situ neutron and synchrotron X-ray diffraction deliver unique and complementary insight into the microstructural evolution of metals at high temperature. Neutrons illuminate a larger bulk volume and reveal quantitative phase abundance, bulk texture, lattice parameter changes and other ensemble averaged quantities. In contrast, fine-bundled high-energy X-rays deliver reflections from a number of individual grains. For each constituting phase, their statistics and behavior in time reveal information about grain growth or refinement, subgrain formation, static and dynamic recovery and recrystallization, slip systems, twinning, etc. While monochromatic methods are well developed, white-beam Laue diffraction is emerging for the comprehensive study of orientation space, allowing to follow the recrystallization process of a fine- to coarse-grained material. Features will be discussed on selected metallic systems, focused on light metals, and an outlook given to build the Materials Oscilloscope.