This chapter is a translation by E. Crull and G. Bacciagaluppi of Grete Hermann's hitherto unpublished manuscript on "Determinism and Quantum Mechanics' from 1933. In this fascinating manuscript, sent by Hermann to Bohr, Dirac and Heisenberg, and rediscovered by us in the Dirac Archive, Hermann criticises known arguments for the incompatibility of quantum mechanics and determinism, including the theorem in von Neumann's 1932 book, and sketches what a completion of quantum mechanics might have to look like.