The rules that goverrn the IRS code are found in Title 26.
The IRS as an Agency, it's mission and statutory authority explained by none other than the IRS themselves. The IRS explains how it is rendering a service and it's responsibilities to Congress' laws in carrying out the responsibilities of the secretary of the Treasury.
It goes on to explain our responsibilities to pay taxes and how they are there to help.
Read an interesting bit about how Congress began the IRS in 1913.
Read about US Tax Code Updates.
