Commissioner v. Glenshaw Glass Co., 348 U.S. 426 (1955), was an important income tax case before the United States Supreme Court. The Court held as follows: * Congress, in enacting income taxation statutes that comprehend "gains or profits and income derived from any source whatever," intended to tax all gain except that which was specifically exempted. * Income is not limited to "the gain derived from capital, from labor, or from both combined." * Although the Court used this characterization in Eisner v. Macomber, it "was not meant to provide a touchstone to all future gross income questions." * Instead, income is realized whenever there are "instances of [1] undeniable accessions to wealth, [2] clearly realized, and [3] over which the taxpayers have complete dominion." * Under this