Pauli's letter praises Dyson's work. He also asks a question about renormalization technique.

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.

Pauli writes about the connection of renormalization with power series expansion. He makes some remarks on the difficulties of meson theories and on mathematical formulation of fundamental laws of nature. He adds some remarks on his mathematical background.

Remarks on the classical H-theorem on critical recapitualtion of ch. VII, 79-82 of Boltzmann's "Vorlesung über Gastheorie", vol. II.

Pauli comments on two treatises by Huygens, the "Traité de la lumière" and the "Discours de la cause de la pesanteur". He also writes on Descartes' theory of vortices.

Pauli gives further comments on Bohm's ideas, in particular on the hidden parameters.

Pauli writes of a letter by de Broglie clarifying the point of view published in: J. Phys. : 8 (1927), pp.225. He also criticizes a recent publication by de Broglie dealing with the Schrödinger equation.

Pauli gives a critical comment on a letter by de Broglie and his attempt to combine a deterministic picture with the wave-mechanical probability,

Comments on E. von Kahler's collection book 'Verantwortung des Geistes', especially on titles 'Ursprung und Wandel des Judenhasses' and 'Das Problem Deutschland'.

Pauli write about the Copenhagen conference and its program.