Heisenberg attempts to explain Källén's difficulty.

Heisenberg talks about Thirring's model and tentative results of Heisenberg's recent calculations.

Heisenberg talks about a detailed report on his calculations, starting with Langrangian.

Heisenberg replies to Pauli's letter. They agree about dipole ghosts. The eigenvalue spectrum has to follow from the theory, if this is correct. He talks about his equation which he regards as the correct equation of matter from which all elementary particles can be derived.

Heisenberg suggests an alternative for his operator O which was criticized by Pauli and develops some results from this new start.

Heisenberg remarks on a probable mistake in Pauli's letter.

Heisenberg asks for clarification of certain of Pauli's arguments.

Heisenberg replies to three letters from Pauli who is in New Yok.

Heisenberg replies to the objections of Pauli in his last two letters, concerning the second draft of their pre print.

Heisenberg writes of the distribution of their common pre print. He suggests the next steps as regards the paper and its disposition.