Pauli preliminarly replies to Heisenberg's last letter. He does not agree with Heisenberg's treatment of the mathematics of the problem. He writes of a recent letter from Princeton with the news about Mrs. Wu's experiments with "killing" parity. He thinks that agrees with a suggestion by Salam who connected the laxk of left-right symmetry with the vanishing of the rest mass of the Neutrino.

Pauli talks more about dipole ghosts. He thinks the indefinite metric is not suitable for solving the problem of elementary particles.

Pauli asks why in Heisenberg's calculations the force-potentials are always real.

Pauli discusses Heisenberg's formulae in his letter of the 13 September 1957.

Pauli dicusses the alternative dipole ghosts or complex roots. He writes on difficulties in the case of Lorentz-invariant interactions. The Tamm-Dancoff approximations are not sufficient in this case.

Pauli writes about the isotopic-spin problem.

Pauli continues his last letter of the 13 December.

Pauli talks about the problem of mathematical formulation of symmetry-violations in the case of the dichotomy connected with the interpretation of dipole ghosts and complex ghosts. He hopes for progress in the question of leptons. There is a more positive attitude on the question of indefinite metric.

Pauli writes on further calculations about the physics of elementary particles, and about more group theoretical considerations. Possibly there exists complementary between the space-time description in the micro-world and the physical probability.

Pauli explains what he means by "antisymmetric metric". Hereby one gets the masses of leptons different from zero.