Dr. Joel Filártiga never forgot the advice that Alfredo Stroessner, the Paraguayan dictator, gave him one day.

Stroessner had come to pay a visit at the sprawling country manor owned by Dr. Filártiga’s father, a wealthy, well-connected tobacco exporter. And after a few drinks, as Dr. Filártiga would recall, Stroessner turned to young Joel and told him: “There are only three things in life that are worthwhile. Power, money and pleasure.”

Stroessner acquired all three, consolidating his grasp as a reviled and ruthless anti-Communist strongman who ruled Paraguay as Washington’s ally from 1954 until he was cashiered in a coup in 1989.

Dr. Filártiga, on the other hand, disregarded Stroessner’s counsel. He abandoned — some say betrayed — his family’s fortune. Rather than pursue pleasure, he instead found personal satisfaction — as the only doctor serving 30,000 poor peasants in what he called his Clinic of Hope in Ybycui, a town 60 miles southeast of Asunción, the capital.