Subchapter A — Civil Actions by the United States (Sections 7401 to 7410)
Subchapter B — Proceedings by Taxpayers and Third Parties (Sections 7421 to 7437)
Subchapter C — The Tax Court (Sections 7441 to 7479)
Subchapter D — Court Review of Tax Court Decisions (Sections 7481 to 7487)