Is it possible that human beings can survive without food and fluid over many years and live on light alone ? Are we confronted with quackery or with forgotten knowledge ? Based on certified reports of personal experiences, interviews and scientifically documented laboratory experiments, the picture follows the phenomenon of 'living on light'. As incredible as it may be, there seems to be evidence that there are people living today and some existing thousands of years back too, who do not need food either to live or to sustain their metabolism.