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.

Pauli's letter discusses some recent Beta-decay experiments in the U.S.A. and their bearing on the parity problem. The two component theory is not tenable in the light of these field theories, a deeper understanding of the parity problem is not possible.

Pauli refers to a paper by Weisskopf concerning the self-energy of the electron, which might be useful to Dirac on his discussion of the logarythmic infinities in the theory of holes. A copy of the paper is mailed to Dirac.

Pauli expresses great doubts as to the correctness of Dirac's quantum-electrodynamical approach. He explains that it is possible that the way to describe the interaction of particles with an electromagnetic field could be fundamentally wrong.

Pauli makes further remarks on Dirac's theory. He withdraws the objection concerning singular processes. He considers ways to derive Einstein's radiation laws. He makes some calculations on low-frequency photons. He comments on higher order corrections of the Klein-Nishina formula. He nnounces the publication of a paper about Dirac's theory.

Pauli makes some remarks on Dirac's theory, particularly on the problem of low-frequency photons.

Pauli quotes and comments parts of a letter of Eliezer. He also writes about a letter of Heitler whose method leads in the case of meson-fields to different results from those made by Dirac. He mentions two papers by Heisenberg and comments on his unitary S-matrix.

Pauli writes of another letter of Eliezer and encloses a copy of his answer to him and he adds some remarks.

Pauli thinks that his new formulation of quantum electrodynamics represents a progress, although he agrees with Dirac that a greater symmetry between space-variables and time-variables seems desirable.

Pauli asks Dirac to help a young jewish cousin of his who was forced to leave Austria for racial reaons and is now in danger to be expelled from Switzerland. He writes about his recent investigations with Fierz on particles with an arbitrary spin. He asks if they could be published in the Proc. Roy. Soc. He makes some remarks on Dirac's paper on the theory of the electron.