Influential economist Alan Greenspan died at 100 from complications of Parkinson's disease. What to know about the diagnosis.

A market maestro to some, he was criticized by others—including himself—for having too much faith in self-regulating markets.

U.S. Federal Reserve Chair Alan Greenspan has died at the age of 100. He died on Monday from complications of Parkinson’s Disease, said his wife of 29 years, NBC News…