The influential economist behind the concept of supply and demand is Adam Smith, often referred to as the "father of modern economics." In his seminal work “The Wealth of Nations,” published in 1776, he introduced the idea that prices are determined by the relationship between supply (the quantity of a good available) and demand (the desire for that good). Smith argued that in a free market, individuals’ actions driven by self-interest inadvertently promote societal benefits, leading to an efficient allocation of resources. This foundational principle remains central to economic theory today.