Many people think that publications by the Internal Revenue Service (IRS) are the definitive source of information about how to file your income taxes, but this actually isn't the case. The tax code, also called the Internal Revenue Code (IRC), is where the actual rules are published. Unfortunately, in addition to being thousands of pages long–in 2014, the IRC was approximately 2,600 pages long–the IRC is not easily decipherable by the average person.