Pauli has received from Rosental a copy of Bohr's article for "Dialectica" and Bohr's letter. This article will be of great help to him to clarify the contents of other articles in the issue, particularly Bohr's definition of "phenomenon". It would be a great help for the general editorial comment on the whole issue, if Bohr could return to Pauli the proofs of Einstein's article and also drop him a line on his opinion about the remarks which Pauli made himself in his letter to Einstein (of which Bohr has a copy). Every criticism is welcome.

Pauli sends Bohr a copy of his article for the Sommerfeld-Festschrift with a few comments. He writes about Kronig's work on band-spectra. He also talks about his good cooperation with Scherrer and about his plans for the vacation.

Pauli is glad to have Bohr's letter of May 11th and he hopes that Bohr will soon be back in Copenhagen. Einstein has sent Pauli an article for "Dialectica", which essentially repeats his old arguments. Pauli encloses copies of his letter to Einstein and also his reply. Pauli did not agree with Einstein's point of view expressed in his letter and he did not continue this correspondence. Pauli urgently needs Bohr's promised article for "Dialectica". A short address clarifying some concepts used by Bohr would be sufficient without any discussions of historical questions. They all hope that Bohr will be able to come to the conference in Zürich.

Pauli thanks Bohr for his letter of the 16th October 1948, containing the revised version of the Einstein article and the "Dialectica" article. He makes some comments on his editorial survey. He asks Bohr about a contribution to a physics meeting in July 1949. He also reminds him of Sommerfeld's 80th birthday.

Pauli refers briefly to a paper by Sachs on the magnetic moment of the deuteron.

Pauli invites Ehrenfest to lecture on X-ray physics in a meeting in Zürich. He refers to the Ellis-Wooster heat experiment.

Pauli makes further remarks about the H-theorem.

Pauli writes on his meeting with Fierz in Basel.

Pauli asks pedagogical questions in connection with the impending seminar on group theory and quantum mechanics. He also makes some comments on Fierz's historical paper.