X-rays, originally a tool for structural investigations and imaging purposes can nowadays be used for studies of the dynamics in materials. In the last two decades a powerful technique was developed using a three-axis spectrometer with crystal optics operating close to backscattering geometry, allowing routinely an energy resolution of 1–2 meV at present synchrotron radiation facilities. The method is extremely attractive for studying the coherent part of the dynamical structure factor of periodic structures like small and complex crystals and of non-periodic structures like amorphous materials, glasses or liquids with high sound velocities. Besides the backscattering technique, a different method was developed in the last years using nuclear resonant absorption. In this technique the partial vibrational density of states of the resonant nuclei can be determined. The sensitivity of the technique allows the study of the vibrational behaviour in very small amounts of material even in nanometer sized thin films or particles, Thus, it delivers information on the influence of reduced dimensionality or of confined geometry on the vibrational spectrum for more insight into the unusual mechanical properties of such new materials.