Soon after it was first described, normal-pressure hydrocephalus became a notable and, it was thought, successful topic for neurologic research. Its mechanism of formation was soon explained and its diagnosis and treatment were prescribed. However, after a series of contradictory reports, confusion replaced certainty. Research has continued, concentrating on predicting the outcome of shunt insertion. The author reviews our evolving understanding of the pathophysiology, diagnosis, and treatment of this entity and offers a strategy to assist in deciding which patients might benefit from shunting.