Short answers, pulled from the story.
The Internal Revenue Code is codified as Title 26 of the United States Code. It divides federal taxation into topical subtitles covering income, estate, employment, and excise taxes.
A codification project resulted in the Revised Statutes of the United States approved on the 22nd of June 1874. Ward M. Hussey served as the principal drafter of the Internal Revenue Code of 1954 when it was enacted on the 16th of August 1954.
The 1954 Code imposed a progressive tax structure with 24 distinct income brackets ranging from 20 percent to 91 percent. Income exceeding $2,000,000 was taxed at the maximum rate of 91 percent during that era.
In 1986, the Tax Reform Act changed the name of the 1954 Code to the Internal Revenue Code of 1986. Subsection (a) stated that the Internal Revenue Title could be cited as the Internal Revenue Code of 1986 while retaining most lettering and numbering from its predecessor.
Section 1 imposes the federal income tax on U.S. citizens, residents, estates, and trusts while Section 11 establishes corporate income tax liability. Section 501(c)(3) grants exemption status to charitable organizations and Section 401 defines qualified pension plans including employer-sponsored retirement options like 401(k)s.