In the 1930's Georg Placzek has completed the theory of Raman scattering and almost twenty years later he has published a concise theory of neutron coherent inelastic scattering. In this way he has laid theoretical foundations to two methods, which have furnished most of our knowledge about elementary excitations in crystalline solids. The neutron technique, although much more exotic due to its necessity of nuclear reactors or large particle accelerators as radiation sources, has the ultimate advantage of probing a large range of reciprocal space of a crystal and hence providing a detailed information on correlated motion of atoms both in space and in time. Its importance has been recognized some 40 years after Placzek's work by a Nobel prize, awarded to B. Brockhouse (together with C. Shull) for his pioneering experimental work, based on Placzek's theoretical predictions.

In my contribution, after this brief historic introduction, I would like to give a review of neutron inelastic scattering activities at the Institut Laue-Langevin in Grenoble (France), which at present operates world's most brilliant thermal neutron source, catering a suite of state-of-the-art experimental facilities for neutron physics. The access to them is open also to scientists from Czech republic, which financially contributes to the ILL operation as a scientific member since 1998.