The Sixth Edition of this widely used casebook includes the usual rich mix of materials and is adaptable to a survey course, a policy-oriented seminar, or a more specialized J.D. or LL.M tax class. Every major topic is accompanied by a skillfully developed problem set and lively notes, questions, policy discussion, and bibliographic references. Highlights of the Sixth Edition include: Coverage of all important developments since the last edition, including the impact of the COVID-19 pandemic on the nonprofit sector; recent legislation and final regulations on the new excise taxes on excessive executive compensation and large charitable endowments, and the unrelated business tax "silo" rules; major antitrust litigation against the NCAA and related legislative proposals to expand the rights of college athletes; and state law developments. Selective discussion of the American Law Institute's forthcoming Restatement of the Law of Charitable Nonprofit Organizations. Division of the chapter on charitable tax exemptions into two chapters, separately covering affirmative requirements for tax exemption (Chapter 5) and limitations on exemptions and procedural requirements (Chapter 6). Updated author's text addressing the robust policy debate over income inequality, "elite philanthropy," and the implications for reform of the charitable deduction. Surveys of proposed tax legislation, including enhanced regulation of donor-advised funds and private foundations. Pruning of dated materials, more tightly edited cases and notes, and several new problems.