In highly correlated electron systems the magnetic interactions lead to the formation of large quasiparticle masses at low temperatures. The aim of this project is to reach a better understanding of the strong electron correlations in heavy-fermion systems (HF) and liquid 3He by studying the magnetic interactions with inelastic neutron scattering. In recent years HF systems have shown a large variety of groundstates with superconductivity, quasi-insulating behaviour and the presence of magnetic instabilities. This large variety of groundstates can not be understood from the existing models. In this project we propose to perform inelastic neutron scattering measurements down to ultralow temperatures and under high pressure in order to study the magnetic interactions of a number of characteristic HF compounds with different groundstates and liquid 3He. The measurements will be performed at the cooperative research group of the Institute Laue Langevin (ILL) and the nuclear centre (CENG) in Grenoble.