To obtain the highest possible resolution has always been a major challenge in high resolution &ggr;‐ray spectroscopy, using crystal diffraction at the Institut Laue Langevin (ILL), Grenoble. About a quarter of a century ago the very first measurements at ILL started with a resolution already sensibly better than the one which could be obtained with solid state detectors. To date &ggr;‐rays emitted after neutron capture can be recorded with unprecedented and unequaled resolving power. In the context of this meeting some key experiments, carried out in the last 25 years, will be discussed. Finally we will try to evaluate where the emphasis might be in the upcoming years. © 2002 American Institute of Physics