Dr. Ehrenfried E. Pfeiffer (1899–1961) was born in Munich. He worked closely with Rudolf Steiner to test and document many of the effects of biodynamic practices. Pfeiffer visited the U.S. several times during the 1930s, and was awarded a doctorate for his groundbreaking theory of Sensitive Crystallization Processes as a blood test for detecting cancer. In 1940, he immigrated to the U.S., where he pioneered biodynamic agriculture and helped establish the Biodynamic Farming & Gardening Association. He died in Spring Valley, New York.