In the United States since the 1930s, the Treasury Department and tax experts has attempted to accomplish a “one package” comprehensive tax reform program to create a simpler, fairer, and more equitable federal income tax system with sufficient ability to raise revenue. However, their attempts to accomplish the kind of tax reform have always failed except in 1986. This paper picks up three episodes of federal tax reform to demonstrate the Treasury’s and tax experts’ significant effort to accomplish a “one package” comprehensive tax reform, and the process in and for which they failed and succeeded: Federal tax reform of 1964, 1978, and 1986. In the meantime, through examining the three episodes, this paper explores how Congress had seriously considered the kind of comprehensive tax reform that the Treasury and tax experts proposed after World War II.