The veneration and appreciation of the Chinese yam or Shanyao (Dioscorea batatas) in China and its neighbouring countries has a long tradition indeed.

In the last decades scientific research has been carried out in these countries regarding its nutritional value as food for humans.

Additionally and quite unexpectedly, confirmation of the importance of this plant came from Europe. As early as 1924 Rudolf Steiner, the founder of anthroposophy, remarked that this is the only plant being able to gather light ether in its roots. For this reason he recommended that in Europe, too, it would be beneficial if this root would be consumed on a regular basis.

Rudolf Steiner's words raise some questions. How should we understand and interpret this observation.

The present book endeavours to answer these questions. It tries to elucidate Steiner's remark on the yam as light root and its relevance for us today.

Theodoor J. Zimmermann