A novel diffraction technique for the local three-dimensional characterization within polycrystalline bulk materials is presented. The technique uses high-energy synchrotron radiation (40 keV <E < 100 keV), which penetrates deeply into materials. Focusing broadband optics have been developed that provide the required intensity and spatial resolution perpendicular to the incident beam. A focus size of 1.2 mum was achieved. Modified crossed-beam techniques are being developed that define the longitudinal resolution, i.e., the component of the gauge volume parallel to the incident beam. We present experimental evidence that a longitudinal resolution down to 10 mum can be obtained. Fundamental materials properties such as the strain/stress state, grain-orientation, -size, and -surface topology can be probed and mapped in three dimensions in favorable cases. Imbedded volumes and interfaces become accessible. The technique is nondestructive and allows for in situ studies of samples in complicated environments. A dedicated experimental station has been constructed at the ID11 beamline of the European Synchrotron Radiation Facility. On-line two-dimensional detectors and conical slits have been developed. Four examples of applications are presented.