Ethnobotanist Mark Plotkin conducts a fascinating interview with William Siff, who is a licensed acupuncturist, clinical herbalist, and ethnobotanist who practices an unusual combination of both Ayurvedic and Traditional Chinese Medicine. Bill is best known to the general public as author of the classic work, "The Plant Medicine Protocol." The interview not only covers Siff's intriguing background and healing approach but answers the questions of what is a plant, what is a food, what is a spice, what is a medicine, and which species like black pepper are all of the above!