The role of analogy in unraveling the fractional quantum Hall effect mystery

This introductory article, intended for non-experts, explains how the analogy to the integral quantum Hall effect provided the key to understanding the fractional quantum Hall effect, at the same time leading to a new class of topological fermions called composite fermions. It is shown how the enormous ambiguity of the original electron problem is eliminated as a result of the formation of composite fermions, and a unique solution is obtained that is extremely accurate and consistent with dramatic experimental observations.