Heisenberg replies to Pauli's letter of 10 March. He gives the result of his latest calculations.

Heisenberg replies to Pauli's letters of 19 and 20 March. He suggests a new version of the interpretation of the theory: she is CP-invariant. Therefore the symmetry is not affected in weak interaction. Further possible consequences of this interpretation.

Heisenberg makes some additional comments on the last results. He resents the letter of Laue about the publicity given to the work. (The letter was sent to him by Pauli.)