The first of the Steiner books in Dutch is from the time that Steiner still stood with one leg in the Theosophical Society of H.P. Blavatsky. He was asked later why he didn’t change the title, but he didn’t want to. Theosophy is the essential Steiner book. In fairly simple terms he gives his view on the world, the constitution of man, what happens when you die and how he came to these ideas. Essential read in any case and when you want to read Steiner, I suggest you start with this one.