Dana Ullman, M.P.H., has authored six books on homeopathic and natural medicine, including The Consumer's Guide to Homeopathy and Homeopathy A-Z. He serves on advisory boards of alternate medicine institutes at Harvard and Columbia schools of medicine, and has also co-taught a course in homeopathic medicine at the University of California at San Francisco School of Medicine. He is widely recognized as one of the foremost spokespersons for homeopathic medicine in the United States. He has been particularly effective in working with major institutions and getting them to change their attitudes and policies toward natural health care. He recently became a consultant to the World Health Organization.