Tom Yoder was frustrated. For six months as a Peace Corps volunteer, he'd worked diligently to earn the trust of an African tribe. He was eager to share with them plans for irrigation ditches, lessons about crop rotation, and new ways to market their surplus fruits and vegetables. But he remained a distrusted outsider.

One day, a young boy came to Tom's hut. He pointed to the far end of the village and said: "The family that lives in that hut has fallen ill. They've been abandoned to die. But the children are my friends. Can you help?"

Tom rushed to the forbidden hut, entered, and immediately realized that the family had contracted yellow-fever. For the next six days, Yoder bathed, fed, and nursed the family until each was strong enough to be transported 90 miles to a hospital. Each family member returned later, completely healed.

The villagers then called Yoder the "great fearless one." From then on they listened to him, accepting all his farming ideas. Tom wrote about this amazing turn in his journal: "It's easy to be fearless when you've been vaccinated against a disease."