Treasury Department Circular No. 230: Regulations Governing Practice before the Internal Revenue Service.
This document is divided in to five subparts:
Subpart A - Rules Governing Authority to Practice
Subpart B - Duties and Restrictions Relating to Practice Before the Internal Revenue Service
Subpart C - Sanctions for Violation of the Regulations
Subpart D - Rules Applicable to Disciplinary Proceedings
Subpart E - General Provisions.