Pauli asks if the last proofs of Bohr's paper are completed; if so, he would like to come to Copenhagen for some talks.

Pauli replies to a question from Bohr, whether an H-theorem can be derived from the point of view of quantum mechanics. He has made no progress in quantum electrodynamics and thinks that a completely new idea is still missing. He writes about Kronig's works and about Nature's introductory remark to Bohr's article.

Pauli urges Bohr again to publish his note on the magnetic electron. He criticizes his note on Beta-rays. Pauli plans to use a short visit to Copenhagen for writing a joint paper with Oppenheimer. He is not satisfied about his joint work with Heisenberg, because of the difficulties of the self-energy of electrons.

Bloch has given Pauli Bohr's letter and the note on the nuclear photo-effect to read. At Bohr's request, Pauli gives his opinion on it.

Pauli has just heard that the second proofs of Bohr's "Dialectica" article have been sent to Bohr. They have to be final and he asks him to return them promptly to the editor. In reading the proofs Pauli noticed a slight error in the German translation of the summary and asks Bohr to correct this. Bohr's article is now excellent. The next time he hopes to write to Bohr about physics again.

This is the last letter from the year 1948, written by Pauli just before going home for a New Year's dinner. Pauli is glad to report that he received the issue of "Dialectica" containing Bohr's article. Unfortunately he cannot say anything on the question of the reproduction rights. He has written to the editor again and hopes that Bohr will soon hear something. Pauli was very glad of the "hopeful spirit" of Bohr's letter. He is very interested in the publication of Bohr's old manuscripts, especially the paper with Rosenfeld on the charge measurements. He also thanks him for the copy of the "penetration" paper. He has had no time yet to look at it, because he was working on the new subtractive electrodynamics. He received a paper by Schwinger on self energy and polarisation of the vacuum. He is a master in concealing physical difficulties with mathematical elegance.

Pauli thanks Bohr for his letter of December, and informs him of the invitation to Oppenheimer to come to Zurich and give some lectures. Pauli says he will probably come to Copenhagen for a conference 6-10 July, and mentions his exchange of letters about physics with Dyson.

Full text: "Konferenz in erster April Haelfte passt ausgezeichnet Vorlesungsbeginn Zürich 20 April = Pauli" (conference in the first half of April suits perfectly lecture beginning Zürich 20 April = Pauli)

Pauli gives critical remarks and some calculations concerning Borns' electrodynamics and his ideas on gravitation.

Pauli replies to Born's question about a possible publication in Helv. Phys. Acta. He expresses his interest in some results (spin) of Born's field quantization.