Heisenberg talks about a reviewed discussion of the mathematical results for the three sectors V, N+2$\Theta$, N+V.

Heisenberg explains that the unitarity of the o-matrix and the positive sign of the norm of stationary states in the Hilbert-space I are two aspects of the same fact.

Heisenberg suggests an outline for a common paper to be published by Pauli and himself.

Heisenberg thanks Pauli for his preprint on the conservation of leptonic charge. He sends by the same mail a first blueprint of the Lee model paper. He writes about further progress in his calculations.

Heisenberg states the points on which he and Pauli agree. He asks Pauli's view on several other points.

Heisenberg puts a question about the transformations of two continuous groups in his "electrical" theory. If this is solved, the problem of strange particles leptons can be tackled.

Heisenberg disagrees with Pauli's letter and gives a new exposition of the relation between $\psi$* and $\psi$+.

Heisenberg comments on his own last letter, in particular on the new formalism he suggested.

Heisenberg replies to Pauli's problem of the mirror-world. He writes on new problems in connection with the eigenvalue question.

Heisenberg resents the publicity given by the press to their work. He sends him by same mail an amended copy of the manuscript.