Now, Thus spoke Zarathustra is another very interesting book. Very, very hard to properly read and understand, Nietzsche purposfully made it in the sty of the byble, making it into an "anti-bible". In his bibliography, the Ecce homo, he wrote that writing Zarathustra only took a few weeks, and he felt like words flowing out from his mind, like he saw revelations. Even he stated, that he himself dont understand everything he wrote, and that he wrote for those, who migth not even born yet. The whole concept of becoming übermensch (overman) is the path to become godlike, and he also present the other end, the "last man", the herd, the NPC, as we know today. Hitler also liked this book a lot, Nietzsche's sister gifted Him a lot of his brothers writings, and his walking stick, after Nietzsches death.