Ende's writing could be described as a surreal mixture of reality and fantasy. The reader is often invited to take a more interactive role in the story, and the worlds in his books often mirror our reality, using fantasy to bring light to the problems of an increasingly technological modern society. His writings were influenced by Rudolf Steiner and his anthroposophy. Ende was also known as a proponent of economic reform, and claimed to have had the concept of aging money, or demurrage, in mind when writing "Momo". A theme of his work was the loss of fantasy and magic in the modern world.