The IRS issues various documents which explain agency positions and provide interpretations of the law, many of which may be cited as precedent.
A Revenue Ruling is the IRS application of law to a particular factual situation but also deemed to be of general interest and therefore published in the Internal Revenue Bulletin (I.R.B.) and later republished in the Cumulative Bulletin. It is not final or conclusive but may be cited as precedent.
A Revenue Procedure is a public statement of IRS practices and procedures that affect the rights or duties of taxpapyers or which should be a matter of public knowledge. It may be cited as precedent.
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A Private Letter Ruling is a written statement from the IRS National Office to the taxpayer (at his or her request) which interprets and applies the tax laws to a specific set of facts. The service does not deem these to be of general interest and therefore does not officially publish or feel bound by them, however, these are important for showing probable IRS approach. (Precedential value controversial. Courts have cited to them but attorneys are not supposed to.
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Advice or guidance furnished by the national IRS office on the request of a District or Appeals office, intended for IRS personal but may be of interest to taxpayers with similar situations. The need for Tax Advice Memorandum may arise during examination of a return or a taxpayer's request for refund or credit. The IRS does not consider them precedential for other taxpayers.
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These documents emanate from the Office of Chief Counsel and indicate the reasoning and authority used in Revenue Rulings, Letter Rulings and Technical Advice Memorandum (not to be confused with revenue rulings issued before 1954 which were also called GCMs). The IRS does not consider these to be precedential, but IRS personnel can use them as guides in formulating positions.
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Prepared by attorneys in the Tax Litigation Division, these are responses from the IRS when a federal tax court issues a decision that is adverse to the IRS. The decisions indicate the reasoning behind the Service's recommendation whether or not to appeal an adverse decision by a trial or appellate court and whether to acquiesce or nonacquiesce in an adverse Tax Court decision, and, since 1993, in trial and Circuit Courts of Appeals as well.
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Compilation of policies and procedures governing IRS administration and operation.
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The IRS website is the best way to obtain tax forms. IRS publicatons are geared for the general public on popular topics and often accompany the forms.