In 1898, Therese Neumann, a nun in Southern Germany, stopped eating and drinking. Apart from the wafer given at Mass, she did not eat again until her death thirty-five years later. Similar cases have been reported over the years--often holy men from the East--and have assumed mythical status. Nonetheless, such accounts remain obscure enough to be safely ignored by modern scientists.

Michael Werner presents a new challenge to sceptics. A fit family man in his fifties and with a doctorate in Chemistry, he is the managing director of a research institute in Switzerland. Unlike those who...