Genesis of tax codes in the United States

Prior to 1874, U.S. statutes were not codified. That is, they were not set forth in one comprehensive subject matter title, but were instead contained in the various acts passed by Congress. Codifications of statutes (including tax statutes) undertaken in 1873 resulted in the Revised Statutes of the United States, approved June 22, 1874, effective for the laws in force as of December 1, 1873 (title 35 of which was the internal revenue title). Another codification was undertaken in 1878.

In 1919, a committee of the U.S. House of Representatives began a project to recodify U.S. statutes which eventually resulted in a new code in 1926 (including tax statutes).

Internal Revenue Code of 1939

The tax statutes were re-codified by an Act of Congress on February 10, 1939 as the "Internal Revenue Code" (later known as the "Internal Revenue Code of 1939"). The 1939 Code was published as volume 53, Part I, of the United States Statutes at Large and as title 26 of the United States Code. Subsequent permanent tax laws enacted by the United States Congress updated and amended the 1939 Code.