The title indicates two possible interpretations, which correspond to the two parts of the book. One suggest, in light of the latest findings of neuroscience and of western philosophy, that there is a physiological limit to the happiness man can reach. Man descends from the animal kingdom and ha has reached this stage in evolution thanks to the biological need to seek satisfaction and happiness - and that is exactly why it is not in is nature to be happy forever. The other interpretation is based on the traditional and eastern wisdom. It invites us to transcend these limits, in order to discover a new stage of possible happiness, through means that unveil new levels of awareness and self-knowledge.