Lichnerowicz reply to Pauli's letter of 15 Nov which has crossed his letter. Pauli's formula is identical to that of Lichnerowicz. He has solved the problem which interests them both and hopes that Pauli will agree to publish a note on it together with him.

Lichnerowicz sends offprints of his recent papers, especially one on the integration of Einstein's equations. He compares his results with those of Pauli's paper in the Annals of Math.

Lehmann, Symanzik and Zimmermann reply to Pauli's letter, in particular about Lee's model and the appearance of "ghosts".

Lehmann makes some remarks about the meson theory and the work of Dyson and Dalitz connected with it.

Yang and Lee discuss several questions: 1) Lorentz invariance in weak interaction, 2) A test of CTP invariance proposed by Wightman, 3) The possibility of measuring the $\mu$ magnetic moment which will afford a test of quantum electrodynamics, 4) The Hamiltonian $\mu$ decay.

Landé asks for references to Pauli's earlier work on classical electrodynamics. He makes a progress report on his "eigenvalue theory".

Landé defines the meaning of a "filter" in his work. He distinguishes it from a potential barrier.

Landé sends manuscript "the ratio of e, c and h" and scattering diagrams invented by Thomas. He discusses the results comparing with them Dirac's theory.

Landau has heard from Weisskopf about Pauli's and Heisenberg's theory and would like to know more about it.

Landau agrees with Pauli on Heisenberg's theory. He makes remarks on Lee's model and future theory.