Social choice theory is a framework for analyzing how individual preferences can be aggregated to reach collective decisions. It explores various voting systems and methods to determine the best way to reflect the preferences of a group, whether in politics, economics, or other areas of decision-making. The theory addresses challenges such as Arrow's Impossibility Theorem, which states that no voting system can perfectly translate individual preferences into a fair collective choice. By studying these systems, social choice theory aims to understand the implications of different decision-making processes on fairness and efficiency in society.