Pauli talks about a manuscript sent by Heisenberg and a question whether unitarity of S-matrix, commutativity of field-operators and regularity of commutators on the light-cone can be fulfilled in the case of abandoning a positive-definite metric. He writes about Wightman's axioms and their inapplicability to physics.

Pauli suggests a note correcting the results of Nishijima. He questions whether Heisenberg's description of physical scattering processes in the Lee model comes to grief through discrete states of negative norm or of complex energy He also asks whether "Heisenberg-models" can be constructed for which the unitarity of the S-matrix is preserved in an indefinite metric of the field-operators?

Pauli talks about Schwinger's contribution to the Handbuch.

Pauli talks about the still existing difficulties with the Handbuch-article and Springer. He writes of his lecture on many-particles-systems. He does not want to touch field quantization for a while.

Pauli doubts some of Källén's formulae for the Lee model. He writes about calculations of convergence of integrals and about the proof for the consistency of Peierl's method.

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.