So far, the world has been dealing with certainty, orderliness, and stability in the social and economic systems. The system in question—social or economic—was taken as a single homogeneous structure. These have defined the thoughts about the method of inquiry and policy and economic theories. In contrast, social and economic systems consisting of real-world problems are complex. A system is called complex when it comprises multiple interconnected elements, parts, or subsystems, and their interactions and feedback loops determine the behavior of the system or economy. It is the interaction between elements that matters. Studying the policy system or economy as a single structure may not provide a reasoned approach. Though challenging, understanding complexity can add an advantage by realizing the hidden potential of interacting elements. For over a century, scholarly research about complexity has brought to the fore concepts that were not realized before. The research in complexity economics at Santa Fe Institute has made a significant contribution since the 1980s. The deeper understanding has added characteristics, such as the interactive nature of elements, emergence, adaptation, evolution, and path dependency, to examine a complex system. Understanding them assumes importance in exploring new approaches and strategies for better policymaking, managing the economy, and meeting the challenges of the twenty-first century.