The basic framework for accounting for income taxes under generally accepted accounting principles (GAAP) has been in place for nearly 20 years. Influential GAAP commentators have recently called for a thorough review of the GAAP tax accounting rules in light of normative accounting theory. Before such a review can take place, GAAP reformers must be armed with an overview of the legal, economic, and practical realities of the corporate income tax in today’s business environment. Nothing in the extant literature provides such an overview. This Article provides that overview, drawing on classic and contemporary authorities from a variety of perspectives. Among other topics, this Article reviews the legal definition of a tax, demonstrates how taxes are noncontractual in nature, discusses issues of economic incidence, reviews the reality of tax planning in today’s business environment, reviews the legal literature that describes the government as a “shareholder” in all firms, and shows the interconnected relationship among GAAP, corporate tax planning, and government enforcement efforts. This Article helps bridge the GAAP and tax law worlds by laying the groundwork for GAAP critics to thoroughly examine and critique the current GAAP rules for income taxes.