Pauli talks about his final views on the formulation avoiding infinities. He is against the tendency of Källén to use cut-off methods. He has a suggestion for a joint publication "on the mathematical structure of Lee's example in renormalizable field theory". He writes a synopsis of the suggested paper.

Pauli writes of Landau's paper "The quantum theory of fields" for the Bohr-Festschrift and comments on it. He says more about the Thirring-model and about Heisenberg's paper on the non-linear spinor-equation.

Pauli writes about Thirring's reply to Pauli's criticism. He talks about an error in Pauli's last letter concerning quantum electrodynamics. He writes about a discussion with Thirring at the Bern-conference about indefinite metric.

Pauli talks about publications in Russia on quantum electrodynamics.

Pauli asks about Thirring's abilities.

Pauli makes some comments on Källén's exposition on "Retarded functions of two variables".

Pauli replies to Källén's letter of the 3 October 1956. He writes about a proof by Symanzik concerning dispersion relations.

Pauli talks about a letter he received from Heisenberg about his recent considerations regarding the Lee model. The problem is where does the unitarity of the S-matrix fail in the case of indefinite metric.

Pauli makes some criticisms of some of Källén's results "not in order to criticize but in order to learn".