Doctors find the management of normal pressure hydrocephalus (NPH) difficult because their diagnosis often is uncertain and the treatment with shunt surgery carries a significant risk. With the aim of bringing to the attention of physicians the useful, but largely anecdotal, information available regarding this problem, this article discusses the epidemiology, reasons why the diagnosis is difficult, differential diagnosis, features of the history, examination, neuropsychologic assessment, radiologic evaluation, and special tests that may help clinicians with management.