Pauli just read in the newspapers that the Germans in Denmark have surrendered, and he sends all his good wishes and congratulations on this event. He does not know whether Bohr is still in the USA, but if so, he would like to meet him in Princeton, New York or elsewhere. It is very important for him to make decisions for his future and it would be of invaluable help for him to talk with Bohr. His relations to the Eidgenossische Technische Hochschule in Zürich (ETHZ) are probably more complicated than he thinks.

Pauli gives his reactions to the articles by Waddington and R Goldschmidt and the latter's book on adaptation and mutation. He writes on Oppenheimer and Delbrück's views. He also comments on Bohr's article "Physical science and the study of religions".

Pauli sends a few informal lines in answer to Bohr's letter of the 3rd March. Meanwhile he has seen Delbrück and received from him a report about his meeting with Bohr in Copenhagen. He said that Bohr changed his mind on these biological questions soon after he had sent his letter to Pauli. This seems to Pauli quite satisfactory as he is now rather convinced that there is no causal connection between the happenings in a gene and the environment (milieu) of the organism. Now Pauli has spoken with Delbrück and also with other biologists he sees much better where the real problems are. Meanwhile another of their common friends, Otto Stern, passed through New York on his trip from California to Europe. Bohr will soon see him in Copenhagen.

Pauli invites Born to contribute to an issue of the Rev. of Mod. Phys. in honour of Bohr's 60th birthday.

Pauli writes that Einstein's philosophical point of view is not "deterministic", as Born believes, but "realistic". He explains it for the case of a macro-body and refutes part of it. He adds remarks classical and quantum mechanics.

Pauli's letter deals with contributions, received and not received from physicists of various countries to the Bohr-issue. He talks about an invitation to visit Russia.

Pauli asks about details of an article by Caldirola on the experimental verification of the relativistic time dilatation.

Pauli is sending a selection of journals, but he thinks that Dutch physicist's expectations concerning the content of American and English periodicals for the years 1940 - 1945 are too high. However, some interesting work has been done in the neutral countries and Russia. In the USA some progress has been made in more technical fields, like microwave, radar and heavy cores. Pauli did not contribute to the secret work, but he worked alone on meson theory and quantum electrodynamics. He was not able to solve any real problem in this domain. The most interesting subjects are now Amaldi's experiments on neutron-proton-scattering and its discussion by Hulthèn and Wentel. Pauli will send Casimir and Rosenfeld a copy of his M.I.T. lectures on meson theory, which will soon be available. He says that the problem of the nature of nuclear forces is no more solved than it was in 1940, and he does not expect the secret material to help when it is published. Pauli encloses Onsäger's solution of a two-dimensional Ising model which he considers a masterpiece. Pauli says that he has been offered a professorship at Princeton, but since he is still a professor at Zurich he feels some obligation towards them and plans to postpone his decision until he has visited Zurich. He discusses the post-war situation in Europe and the U.S.A. and says that he feels himself to be a European.