[en] Complete text of publication follows. The study of nuclear structure at the limits of angular momentum and isospin is only possible with very selective and powerful detection setups. The EUROBALL γ-ray spectrometer and the many associated ancillary detectors have been designed for that purpose. In its fourth phase, EUROBALL includes an inner BGO ball which works, with the Ge detectors and their suppression shields, like a multiplicity filter and a calorimeter and improves the selectivity of the device. EUROBALL IV is in operation at IReS-Strasbourg since june 1999. More than 20 experiments have already been performed with this very efficient instrument and preliminary results of some of them will be presented in this talk. (author)