A survey of the nuclear-structure studies through the nuclear-spectroscopy investigations as performed by different tools and techniques is presented. Starting from the simple radioactive decay studies and the associated γ-ray spectroscopy, since the pioneering work with the first scintillation devices, the review will cover the investigation of disintegration schemes and the scintillation spectra analysis performed in the 50's and the early 60's either by radioactive decays or with direct reactions such as stripping and pick-up and inelastic and quasi-free scattering. Examples are the results obtained for determining single particle and collective states in light and medium heavy nuclei. The selection of nuclear states from the first revolution in nuclear spectroscopy given by the scintillation detectors to the second revolution which allowed a more appropriate selection of nuclear states due to the advent of in-beam γ-ray spectroscopy and heavy-ion nuclear reactions is reviewed. The third and fourth revolution in nuclear spectroscopy given by the advent of more sophisticated γ-arrays and by the possibility of accelerating radioactive beams are also accounted for. In this context as a typical nuclear spectroscopy investigation the revival of the 1f_7/2 spectroscopy is reported with the aim to show the still attractive future of important aspects of nuclear physics.