Reprint of an article by Jean Serpe on the magnetic momentum of nuclear particles.

Letter from W. Pauli to E. Panofsky. Breughel.

Reflection on theory and experiment. Preparation for the 3rd Zurich talks.

Pauli sends his impressions from the Solvay Congress. He writes that the pioneers of quantum physics have become their own epigones, they lost the feeling of intellectual adventure and acquired the attitude of technicians.