So-Called Dollars are a type of exonumia, often commemorative or souvenir tokens, issued in the United States to celebrate historical events or significant occurrences. They are typically not official currency but are collectible items that include various designs and themes. The term "So-Called Dollars" originated from the 1937 book by Harold M. A. Heller, which documented these tokens, particularly those that were issued around the time of the American Revolution, including a notable series from 1776. Many of these pieces often feature themes related to independence, important figures, or commemorations of events like the Centennial Exposition.