Pauli letter collection: letter to Gunnar Källén

Pauli agrees with Källén about the correctness of the mathematics of the Lee-model. He writes on a question where to publish the paper. He agrees with Källén that Heisenberg's idea about the derivation of the electromagnetic field from spinor-fields must be wrong. He hopes that an improved renormalization mathematics might lead to a sort of eigenvalue-problem for the fine-structure constant.