Pauli writes on his timetable for the next two months. He talks about the manuscript of Heisenberg's lecture on Planck, on Fierz's calculations. If one introduces an indefinite metric (e. g. the Lee-model), one has to expect an integral equation for the field.

Pauli replies to a letter of the 24 February 1958. He writes about his work with Heisenberg in general and criticizes emphatically Heisenberg's radio publicity. He makes some remarks on biology and neo-Darwinism.

Pauli discusses Schwinger's paper "A theory of fundamental interaction" published in Annuals of Physics2, 407, 1957 which treats the mirror problem in an alternative way.

Pauli writes on the mirror problem and the group-invariance problem.

Pauli discusses details of Gürsey's idea about the isospin.

Pauli asks for details about Gürsey's formalism with a non-degenerate vacuum. He enumerates several problems which worry him, e.g. mirror states, classification of elementary particles, etc...

Pauli returns briefly to the mirror problem.

Pauli makes further remarks on Gürsey's formulation.

Pauli expresses satisfaction over Gürsey's idea to make the neutrino rather than the vacuum responsible for strangeness. He discusses several difficulties connected with the spinor-model.

Pauli writes about his renouncing the partnership with Heisenberg. He thinks there are mistakes in Heisenberg's integration of his equation. Further, if one attempts to loosen either the causality or the unitarity of the metric, this leads to disastrous results in relativistic theories. His impression is that one has to wait for new physical ideas, because mathematical virtuosity alone cannot lead to the discovery of new laws of nature.