zur Atherforschung und Ernahrung, zur ... Briefe und Aufzeichnungen aus dem Nachlass, Perseus-Verlag, 2000. . (German) Henry Barnes, Into the Heart's Land: A century of Rudolf Steiner's work in North America, SteinerBooks, 2005. , Chapter 19. Kevin T. Dann, Across the Great Border Fault: The naturalist myth in America, Rutgers University Press, 2000, . Alla Selawry, Ehrenfried Pfeiffer: Pioneer of spiritual research and practice: A contribution to his biography, Mercury Press, 1992. Alla Selawry, Ehrenfried Pfeiffer: Pionier spiritueller Forschung und Praxis: Begegnung und Briefwechsel: ein Beitrag zu seiner Biographie (Pioniere der Anthroposophie), Philosophisch-Anthroposophischer Verlag am Goetheanum, 1987. . (German) External links The Pfeiffer Center, Chestnut Ridge, NY 1891 births 1961 deaths Agricultural writers Anthroposophists Emigrants from Nazi Germany to the United States Organic farmers People from Chester, Orange County, New York Scientists from Munich People from Spring Valley, New York People from the Kingdom of Bavaria