Pauli welcome's Jauch's impending appointment in Princeton University and gives advice as to the negotiations about working conditions. Enough time for research is vital. He comments on the difficult paper by Dirac. He suggests a problem in the same area (application to "infra-red catastrophe"). He writes of his plans for a joint investigation with Kusaka about application of the strong-coupling formalism on a mixture of mesons of zero spin and spin 1 (Rosenfeld-Möller theory).