A new series from the National Academy of Sciences explores the broad role of social science research in benefitting society. This episode profiles a man named Fielding Daniel and his wife, Amy, who were told to wait years so that Daniel could get a kidney. This led them to the market economist Alvin Roth, whose research and redesign of the kidney marketplace saved countless lives. Roth pinpointed the main problem: There were lots of people who wanted to give kidneys but couldn't because their loved ones weren’t a match. "As an economist that's not the way an orderly market works," he explains in this short film. "So, I got together with some colleagues and said let's think how we would trade kidneys."