Heisenberg writes of his progress as regards the eigenvalue problem. He writes about the contents of a preprint.

Heisenberg talks about the univalent definition of the Lagrangian by the groups and about the mirror problem.

Heisenberg writes about his trouble with the journalists and the statement he has made for the press. He talks about recent results of his calculations.

Heisenberg writes about the progress of his work, together with Dürr, Schliederand Yamasaki. They are going to describe the theory for nucleons and Pi-mesons. Heisenberg gives an explanation of their ideas.

Heisenberg asks for Pauli's opinion on his Zeeman effect paper.

Heisenberg explains his ideas about the "Vertauschungsrelationen" (interchange relations) in his paper. The real problem arises after the introduction of an interaction. This belongs to the general question: which invariance conditions are fullfilled by the interaction energy? He is not as pessimistic as Pauli, the whole question boils down to the problem of finding suitable expressions for interaction out of combinations of wavefunctions which obey regular interchange relations. One has to begin by forming models for unitary theories which afterwards will split up in theories for single particles. The postulate of "hermiticity" is connected with the conservation law for nucleons.

Heisenberg thanks Pauli for the invitation to the symposium in Zurich.

Heisenberg comments on Pauli's calculations on the Lee model. He writes about his own work, especially on Bosons of zero mass in his model.

Heisenberg writes on the application of Pauli's ideas to quantum electrodynamics and on the avoidance of ghosts.

Heisenberg talks about some relations between Lee's theory and his.