Arrow's Impossibility Theorem is a concept in social choice theory that demonstrates the challenges of creating a fair voting system. Proposed by economist Kenneth Arrow in 1951, the theorem states that no voting method can perfectly translate individual preferences into a collective decision while satisfying a set of reasonable criteria, such as fairness and consistency. The theorem outlines five criteria that any voting system should ideally meet: unrestricted domain, non-dictatorship, Pareto efficiency, independence of irrelevant alternatives, and transitivity. However, Arrow proved that it is impossible to satisfy all these criteria simultaneously in a democratic voting process, highlighting the complexities of collective decision-making.