The method of backscattering that is applied in neutron spectroscopy in the microelectron-volt region is described, as is its development at the Jülich Research Reactor FRJ-2, and at the Institut Laue-Langevin in Grenoble. Selected examples of experiments are presented. The backscattering principle can be applied for high-precision measurements of lattice parameters (Δa/a 10-7) as developed at the Jülich reactor.