Deflation
Deflation occurred periodically in the U.S. during the 19th century (the most important exception was during the Civil War). This deflation was at times caused by technological progress that created significant economic growth, but at other times it was triggered by financial crises — notably the Panic of 1837 which caused deflation through 1844, and the Panic of 1873 which triggered the Long Depression that lasted until 1879. These deflationary periods preceded the establishment of the U.S. Federal Reserve System and its active management of monetary matters. Episodes of deflation have been rare and brief since the Federal Reserve was created (a notable exception being the Great Depression) while U.S. economic progress has been unprecedented.
Great Depression in the United States
Nobel laureate economist Milton Friedman and his fellow monetarist Anna Schwartz argued that the Federal Reserve could have stemmed the severity of the Depression, but failed to exercise its role of managing the monetary system and ameliorating banking panics, resulting in a Great Contraction of the economy from 1929 until the New Deal began in 1933. This view was endorsed by Fed Governor Ben Bernanke who made this statement in a speech honoring Friedman and Schwartz:
Let me end my talk by abusing slightly my status as an official representative of the Federal Reserve. I would like to say to Milton and Anna: Regarding the Great Depression, you're right. We did it. We're very sorry. But thanks to you, we won't do it again.
— Ben S. Bernanke