On Aggression (German: Das sogenannte Böse zur Naturgeschichte der Aggression) is a 1963 book by the ethologist Konrad Lorenz; it was translated into English in 1966. As he writes in the prologue, "the subject of this book is aggression, that is to say the fighting instinct in beast and man which is directed against members of the same species." (Page 3)According to Lorenz, animals, particularly males, are biologically programmed to fight over resources.