Ehrenfried Pfeiffer (1899-1961) was a German scientist, soil scientist, leading advocate of biodynamic agriculture, anthroposophist and disciple of Rudolf Steiner. Pfeiffer was a pioneer of biodynamic agriculture in Europe, Britain, and America. He is most widely known for his innovative work in composting. He conducted extensive research on the preparation and use of biodynamic compost and was is the inventor of BD Compost Starter, a compost inoculant.