Linda Johnston, MD, completed her medical training at the University of Washington in 1979 and started practicing homeopathy in 1986. She has been teaching homeopathy for more than 20 years. The author of scholarly and popular books on homeopathy, Johnston's recent projects include a book on the treatment of children using new homeopathic techniques. She lives in Texas with her husband, Frans Vermeulen. 

Frans Vermeulen, is a Dutch homeopath and one of the world's foremost authorities on homeopathic materia medica. Vermeulen is the author of some of the most popular modern materia medicas, including Concordant Reference, Synoptic Reference Vol. 1 and Vol. 2, and upcoming Prisma Reference Materia Medica. With his wife, Dr. Linda Johnston, he has co-authored four volumes on plant remedies.