In 1994, the discovery of a quantum critical point and non-Fermi liquid behavior in the phase diagram of heavy fermion compounds by H. von Löhneysen et al. led to a new rise of interest in the research of these compounds. Another experimental breakthrough was the demonstration in 1998 (by the group of Gil Lonzarich) that quantum criticality in heavy fermions can be the reason for unconventional superconductivity.