The Written World of God is the first systematic overview of the science of letters ('ilm al-huruf) according to the great Andalusian spiritual master, scholar, poet and philosopher Ibn 'Arabi (d. 1240). Ibn 'Arabi defined the science of letters as familiarity with the building blocks of the Quranic revelation and everything in the world of nature. Letters are understood as visual and aural signs pointing to the mysteries of existence. The present study examines how the universe came to be, for what purpose it was created and the hierarchical structure it is endowed with. It is an old story told anew - through the 28 letters of the Arabic alphabet, their orthographic forms and the meanings attributed to them, using Ibn 'Arabi's own diagrams. Although the story could be told through geometric figures or numbers, letters were chosen on the basis of Ibn 'Arabi's doctrine that the meanings carried by the letters fully encompasses the whole of existence: God and the universe.