Join Tara Stewart in an in-depth exploration of the Fourth Bureau Definitive Issue, also known as the Regular Issue, of U.S. stamps produced between 1922 and 1930 by the Bureau of Engraving and Printing. Due to technological advancements and economic experimentation during this era, many stamps share identical images but are considered different due to their unique production methods. This creates a lot of confusion when you are trying to collect this series. And these differences can affect the stamp’s value dramatically—from as little as $0.25 to over hundreds of thousands of dollars.