Acquiring knowledge about microstructures and textures is crucial for the improvement and development steel products, because these two characteristics are controlling factors for the properties of steel. Diffraction techniques using X-rays, electrons or neutrons are suitable to study microstructures (e.g. phase relationships) and textures (crystallographic orientations). X-ray diffraction (XRD) and electron backscatter diffraction (EBSD) are generally available techniques within an industrial research environment. Different examples from daily research within Corus RD&T are shown, where these diffraction techniques have been used. For the development of new high-tech multi-phase steels we study phase composition and microstructure to optimise product properties. Retained austenite may easily be detected and quantified by XRD, using the right approach. Moreover, using an area-sensitive 2D-detector, such as e.g. the GADDS system, the textures of ferrite and austenite components may be identified simultaneously during a single measurement. Micro XRD (beam diameter down to 100 mu m) allows us to study small-scale welding joints within TRIP steels and how these welds evolve with time. Even more interesting is the possibility to study recrystallisation and phase transformations in situ at high temperature in real time, e.g. to make phase transformations visible during inter-critical annealing. Another fascinating and beneficial attribute of XRD and EBSD is to study coatings/platings such as Ni in relation to the underlying steel substrate. Not only it is possible to identify the thickness of a plating or the phases in a coating, but textural and microstructural relations between the substrate and the surface layer can also be visualised. The understanding of microstructure opens the way to grain boundary engineering in coated products to help improve the corrosion properties.