Watching the action in functional materials becomes possible in great detail due to major advances in instrumentation (intense beams, novel detection systems, combination of analytical methods), software development and big data managment. Powder diffraction and scattering is the main tool for structural investigations under in-situ and in operando conditions in the emerging fields of chemistry, biology and physics. Functional materials of interest are magnetic systems, battery and fuel cells, solar cells, but also systems for drug release in bio-environements. Powder diffraction and scattering techniques can also combine complex sample environments (temperature, reactions, humidity, mechanical load, fluidics) with additional X-ray based techniques (i.e., fluorescence or absorption/phase contrast tomography) and complementary analytical methods (i.e., Raman or IR Spectrometry). Solid state structural transformations can be studied in great detail related to todays achevements  in spatial and time resolutions.