Pauli is against Heisenberg's approach to quantum electrodynamics. It is impossible to work only with energy-momentum values and the S-matrix and to disregard space and time. He talks about some clarifications on his own last letter but one. He writes on the separation of purely mathematical quantities from physically significant ones.

Pauli replies to Lüders' letters of 8 Dec and 13 Dec about elementary particle theory.

Pauli replies to Källén's letter of the 13 December 1957. Pauli agrees with him that the indefinite metric is the correct way. He talks about the macroscopic space-time description with complex roots and the Bisection of zero-states in parts corresponding to the upper and lower half-plane which must be connected with the difference between observed object and observing subject. By this bisection symmetric violations are introduced in a most natural way. He writes on his discussion with Heisenberg and on complex ghosts in weak interactions.

Pauli replies to Heisenberg's letter of the 16 December and discusses the formalism and correction of a mistake Pauli made. He writes on group theoretical considerations.

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.