This book offers a comprehensive reflection on the existential condition of the 21st century. Being posthuman, in the 21st century, entails awareness of inter-being: from our symbiotic co-evolutions to the rights of Nature; from the geological time of the Anthropocene to the rise of Big Data and artificial intelligence. In ecology, biology, technology and ontology, the manifold paths of posthuman self-realization will reveal that we are all co-creators in the existential unfolding: our lives are our ultimate works of art.