Max Aub's work is characterized by a labyrinthine, obsessive and many-sided inner world, which could be expressed only when allowed. Therefore, it is not strange that the complete elaboration and the revision of Aub's personal notes offer numberless happy discoveries. Working as editor of Campo de sangre within the frame of Obras completas published by the Biblioteca Valenciana, my most important finding was that of many notebooks (fifteen by now) including the skeleton and first notes of the novels. The target of this article is to reconstruct the genesis of this novel, starting from that autobiographical materíal and making some hypotheses to give an account of the radical turn from the first ideas of Campo de sangre to the definite writí...