It is no surprise that economics, with its intertwined principles, theories and abundant real-world examples, can have a staggering influence on the outcomes of investments. We can look to the past, to prominent economists like Adam Smith, whose insights into the nature of supply and demand informed our understanding of how prices would be affected by rational decision-making. In the present, we can observe how the seeds Smith planted 250 years ago continue to feed our knowledge of how investments work.