'Philosophy begins in wonder,' said Plato. Descartes agreed that 'wonder is the first of all emotions'.
Wonder is the impulse behind all scientific and philosophical endeavour, art and spirituality.
It is the most fruitful human sense: fuelling our creativity; firing our curiosity; inspiring us to hope and to dream.
But our sense of wonder - that feeling we had as children seeing the Milky Way for the first time - gets used up.
Faced with mortgage and money, we trade a sense of wonder for a sense of reality. And with the world getting ever more complex, reality too often brings anxiety and unhappiness.
Francesco Dimitri argues that this is because we have lost touch with our sixth sense - that of wonder.
By exploring the nature of wonder in many areas of human experience - in religion and spirituality; in myth and folk tales, in modern science and technology - he sets out to show how we can reclaim our sense of wonder - not to become children again, but to become happier and more fulfilled adults.