In 1924, Rudolf Steiner had just completed his lecture course on biodynamic agriculture and was waiting for a car to take him to the station. Suddenly he was approached by two of his pupils with an urgent question: Would his new indications for treating soil and vegetables be sufficient to provide "nutrition appropriate to our times and in accordance with the spirit?" Steiner's frank response was somewhat surprising: "It will not be sufficient even in the most favorable circumstances. What should be done is to cultivate the Dioscorea batatas (the Chinese yam) in Europe so that it can take over from the potato as the staple diet." In the many decades since that conversation, various attempts have been made to cultivate Dioscorea batatas--the "light root"--in Europe, initially by Steiners close colleague Guenther Wachsmuth. More recently, biodynamic farmer Ralf Roessner began to research the plant and its background, but soon discovered problems with the specimens available in Europe. Unsatisfied with the standard of the plants, in 2002 he traveled to the original growing areas of Dioscorea batatas in China, where he was able to form a comprehensive picture of the best planting methods and conditions. He wrote, "The nodules I found and brought back with me showed similar light ether characteristics to the original plants of Wachsmuth." Having successfully cultivated and marketed this light root, Roessner presents some carefully assembled introductory materials based on his experiences and those of a colleague. This small book, illustrated with colour images, is intended for people who wish to discover more about the plant's being and spiritual mission as a "helper of progress." Roessner explains how the light root stores "light ether" i