Potier sends some reprints on mathematics of quantum field theory.

Polvani forwards the written response by M Born to Pauli's criticism at Firenze Conference in 1949 (attached).

Polkinghorne replies to Pauli's remarks about the B-field, with reference to some work by R Shaw. He talks about the paper on $\mu$-decay by Salam.

Perucca sends a reprint on a unified system of units. He gives his views on it.

Peierls offers a proof of the Jacobi identity, and reports on progress in his work on non-local field theories,which includes finding a method which leads to reasonable solutions of the action principle.

Peierls refers to the Møller-Kristensen theory. He says that the difficulties with their theory may arise from discontinuities in the form factor.

Peierls replies to two letters by Pauli. He comments Pauli's calculations as regards the non-local field theory, and on his view about the use of form-factors which may destroy the gauge invariance.

Peierls describes calculations with non-linear expression.

Peierls writes about the methods of renormalization in field equations.

Peierls replies to Pauli's comments on his theory.