Franco Modigliani made seminal contributions to many areas of economics and finance, most notably monetary analysis, consumer spending and saving, and corporate finance. He is most closely associated with the life cycle model of saving and the MM (Miller-Modigliani or Modigliani-Miller) theory of corporate capital structure, both of which remain bedrocks of thought on these topics. A winner of the Nobel Prize, he is the only person to have served as president of the Econometric Society, the American Economic Association and the American Finance Association. He was an adviser to (and co-author with) many students, including two future prime ministers, and was outspoken on policy in both the US and his native Italy. Modigliani was an essential part of MIT economics, and his effervescent personality and enthusiasm added a spark to the department.