Starting in the 1960s, Duke was an ecologist with the United States Department of Agriculture (USDA), joining Battelle Columbus Laboratories (1965-71) for ecological and ethnobotanical studies in Panama and Colombia. During this formative period, Duke lived with various ethnic groups, pursuing what became a lifelong passion for learning from peoples whose traditions are rich with knowledge of the healing properties of plants. Eventually, Duke became chief of the USDA Medicinal Plant Resources Laboratory.

Duke's book, The Green Pharmacy (St. Martin's, 1997), is the standard setter in its field, having sold over one million copies in English. It is now translated into eight languages. Duke has also authored or co-authored 40 other books on herbs, spices and foods, along with 400 articles (half in peer-reviewed journals). He remains a popular lecturer on the subjects of ethnobotany, herbs, medicinal plants, and new crops and their ecology.

In 1995, Duke retired after 30 years with the USDA. Before retiring, he brought his Father Nature's Farmacy database online at USDA. It is now one of the most frequently consulted databases with the Plant Genome Project at USDA. Duke's database is especially useful for determining biological activities and healing potentials of food ands herbs.

For further information: www.greenpharmacy.com.

Please tell us how you first fell in love with plants.

There was an old man across the street from me in the Birmingham, Alabama suburbs that had his rabbits to talk to, and every now and then he would walk me through the nearby woods in the foothills. He taught me about chestnuts when we had chestnuts, and watercress. That was when I was about age five, and I think he was about as old and gangly as I am now. We both profited from these mutual walks through the woods. And I have been in love with botany ever since.

All of us learned in grade school that many of the first European explorers set sail across the ocean in search of spices. I personally love spices but I can't really see risking life and limb to procure them. What's your take on this?

I have a bad poem on that. It only takes four or five lines. I recited this in '92 when it was the 500th anniversary of Columbus setting sail. The poem goes like this: "Columbus set sail/looking for black Indians and black pepper/and he took the wrong ocean/and he found red Indians and red pepper/and he changed the cuisine of the world." As of today, capsicum (red pepper) is one of my ten favorite medicinal spices, and one that is recommended for certain maladies that I have.

What are some of your other favorite spices?

Two years ago, I would have said that garlic is the most important in my garden. Garlic is in more than 20 plots of the 80 plots in my garden. It's also good for some of my ailments. It's a constant battle in my mind over which is most important to me. But garlic is so good to eat and so easy to grow, that I can find it in one condition or another in my garden year-round.