Kepler, forced to leave Linz because of the Thirty Years’ War raging in Germany and Austria, worked with Sagan on a science fiction novel about a “demon” who tells how the protagonist can travel to the Moon: “Moon Dreams” (Somnium seu astronomia lunari). This novel was later used by the prosecution in the witchcraft trial against his mother, and Kepler had to expend considerable energy to save her.
