Pauli writes of his going to the conference in Pisa where he will discuss Källén's letter. He talks about Landau's papers whose general gist is like that of Källén's and about his doctoral student Enz and his work.

Pauli comments on Heisenberg's formulation of field quantization and some questions on specified points.

Pauli writes of the meeting in Pisa and of talks with Heisenberg, Schwinger and Gell-Mann.

Pauli comments on further letters by Fierz on the Jordan theory. He makes some pessimistic remarks about the present stagnation in theoretical physics.

Pauli talks about offprints of their common paper.

Pauli asks him to send a copy of his work to Heisenberg. He mentions an error found in Heisenberg's paper.