The Internal Revenue Service is the principal Federal agency responsible for interpreting and enforcing the Tax Code. Statistics on IRS audits, collections, service, staffing, etc., are posted on the TRAC Web site.
IRS Web site is an good source for IRS forms, Publications and selected other tax-related materials (www.irs.gov). You can link to most of the key materials through the Electronic Reading Room.
You can get most other important IRS materials from Lexis and Westlaw or the leading subscription-based online tax services: RIA's Checkpoint, Tax Analysts' Federal Research Library and the CCH Standard Federal Tax Reporter on Intelliconnect. You can find many obscure IRS materials in the TNT databases on Lexis (TAXANA;TNT), Westlaw (TNT) and the Federal Research Library.
If you need to contact the IRS, you can try the phone numbers on the official How to Contact the IRS page. To contact the IRS attorney(s) working on a particular Code section or Regulation, see the "Code and Subject Matter Directory," Chart 5425 from the Office of Chief Counsel Telephone Directory posted here and here by Tax Analysts. For more detail, look in Tax Analysts' The Tax Directory (info on the TA web site).
Some sources I have used to get individual IRS materials are listed below.
Acquiescence and Non-Acquiescence: If the Tax Court decides against the IRS position on an issue, the IRS will sometimes issue a statement saying that they either accept the Tax Court's argument (acquiesce) or disagree with it (non-acquiesce). To find out whether the the IRS has issued an Acquiescence and Non-Acquiescence to a particular case, look in the RIA Tax Citator; they may also show up in Shepards on Lexis or KeyCite on Westlaw. Note: In addition to the print, the RIA Tax Citator is available on Checkpoint and Westlaw (RIA-CITE).
Actions on Decisions: AODs back to 1997 are posted in the IRS Electronic Reading Room. They are also available on Westlaw (FTX-AODs) and Federal Research Library back to 1985.
Adverse determination letters: When the IRS turns down a request from an organization for tax-exempt status, the Service send the organization an adverse determination letter stating its reasons and providing information on how the organization can appeal the determination. For more, see the "Exemption Rulings and Adverse Determination Letters" section of the Tax-Exempt Organizations entry.
Announcements: Announcements are published in the Cumulative Bulletins and Internal Revenue Service Bulletins, discussed in the "Bulletins" section, below. They are searchable in a database with IRS Notices on Westlaw (FTX-ANN) and the Federal Research Library.
Bulletins (CBs & IRBs): Internal Revenue Bulletins (IRBs) are published weekly by the IRS and compiled into Cumulative Bulletins (CBs). They include IRS Revenue Rulings, Revenue Procedures, Announcements, Treasury Decisions, Geral Council Memos, Tax Conventions, Notices, etc. - plus selected Executive Orders and court cases.
The IRS publishes paper copies of IRBs/CBs. They are reprinted at the end of RIA's Federal Tax Coordinator. They are posted in digital format in the HeinOnline "U.S. Federal Agency Documents, Decisions, and Appeals" library from 1919-2008 (subscription required).
The complete contents of IRBs/CBs are posted on the IRS Web site back to 1995 (www.irs.gov/businesses/topic/index.html). They are also available through the Federal Research Library from 1987, Checkpoint from 1996, Lexis from 1956 (TAXRIA;TNT) and Westlaw from 1919 (FTX-CB).
The form for pulling documents from CBs and IRBs on Lexis and Westlaw is "1985-8 cb 550" or "1985-8 irb 18". Lexis goes back to 1956 and Westlaw goes back to 1954. You can pull CBs all the way back to 1919 from Westlaw if you call (800-733-2889) and ask for the "WL" citation.
Chief Counsel Materials: Chief Counsel Advice, Chief Counsel Bulletins and other materials produced by the Chief Counsel are posted IRS Web site; you can find them in the Electronic Reading Room section of the IRS Web site, although if you're looking for something specific you may find it easier just to search with Google.
Circulars: See "United States Treasury Department."
Cumulative Bulletins (CBs): See Bulletins, above.
Delegation Orders: Are first published in IRBs (see Bulletins, above). They also have their own database on Westlaw (FTX-DO).
Determinations: Written determinations are on Westlaw (FTX-WD).
Enrolled Agents: Enrolled agents are individuals who are licensed by the IRS to represent taxpayers before the IRS. IRS enrolled agents are listed on the National Association of Enrolled Agents Web site. Treasury Department Circular 230 explains the Regulations Governing the Practice of ... Enrolled Agents ... Before the Internal Revenue Service. More information is available on www.irs.gov.
Executive Orders: Are published in IRBs and CBs (see Bulletins, above). In addition, they have their own database on Westlaw (FTX-EO).
Exemption Rulings: Are on Westlaw (FTX-EXEMPT) and the Federal Research Library. See also "Tax-Exempt Organizations."
Field Service Advice: FSA's were written guidance provided by IRS Office of Chief Counsel to local IRS agents from 1992 through 2003. FSAs are available on Lexis (FEDTAX;FSA), Westlaw (FTX-FSA), the Federal Research Library, Checkpoint, and the CCH Standard Federal Tax Reporter on Intelliconnect.
Field Directives: Field Directives are included in the Tax Notes Today database. The database is available on the Federal Research Library, Westlaw (TNT), Lexis (TAXRIA;TNT) and Dialog (File 790).
Forms: See separate entry for "Tax Forms."
General Counsel Memoranda: Are available in the Cumulative Bulletins and Internal Revenue Bulletins discussed in the "Bulletins (CBs & IRBs)" section, above.
Note: The Westlaw GCM database (FTX-GCM) covers only 1962 to 2002. The Lexis database for GCMs (FEDTAX;GCM) covers only March 1967 through November 2002; selected documents available from October 1958 through March 1967. For complete coverage use the IRB or CB databases discussed in "Bulletins (CBs & IRBs)," above.
Handbooks: The "Appeals Returns Processing and Control Handbook," formerly published as Section 220.127.116.11 of the Internal Revenue Manual has been revised and recodified as Section 8.20 under the title "Appeals Records and Processing Manual." See the Manual section, below.
Industry Specialization Program (MSSP) papers: See Papers, below.
Internal Revenue Bulletins (IRBs): See Bulletins, above.
Internal Revenue Manual: See Manual, below.
Letter Rulings: See Private Letter Rulings, below.
Market Segment Specialization Program (MSSP) papers: See Papers below.
Manual: The IRS posts posts a free edition of the current Internal Revenue Manual. CCH sells a print edition. The Manual is also available on Lexis (CCHTAX;CCHIRM), Westlaw (RIA-IRM),
the CCH Standard Federal Tax Reporter on Intelliconnect, and the Federal Research Library. The manual is published in three parts, and the "IRS Audit Manual" refers to the auditing part.
Historical editions: The the Federal Research Library has quarterly historical editions of the manual back to 2001. Westlaw has anual historical editions back to 1997, except for 2004 (FTX-IRMxxxx).
Memoranda: See "General Counsel Memoranda" or "Technical Memoranda," both in this index entry.
Notices: IRS Notice are published in the Cumulative Bulletins and Internal Revenue Bulletins discussed in the Bulletins section, above. They are searchable in the Federal Research Library, the CCH Standard Federal Tax Reporter database on Intelliconnect. and Westlaw in the FTX-ANN database, which has both Notices and Announcements.
You can KeyCite a Notice on Westlaw using its Westlaw number.
Orders: See Delegation Orders, Executive Orders or Treasury Department Orders, all in this entry.
Papers: Industry Specialization Papers (ISPs) and Market Segment Specialization Program Papers (MSSPPs) are available in Tax Analysts' Tax Notes Today and therefore probably show up in Tax Analysts' Federal Research Library, as well Lexis (FEDTAX;TNT
) and Westlaw)(TNT). They are also available on Checkpoint under "Federal Source Materials > IRS Practice."
Private Letter Rulings: Private Letter Rulings (PLRs) are written by the IRS National Office in response to taxpayer questions. PLRs cannot be cited a precedent, but they are still widely read and widely available. The IRS does not officially publish PLRs, but they are posted on an IRS Web site back to January, 1997 in the Electronic Reading Room.
In addition, PLRs are reported in TNT (on Lexis, Westlaw and the Federal research Library) and in BNA's Daily Tax Report the day after they become available.
You can get older PLRs on on Lexis (FEDTAX;PLR) and Westlaw (TA-LTR) back to 1954. The form for pulling PLRs on Lexis is: "plr xxxxxxxx".
PLRs are also available from the CCH Standard Federal Tax Reporter on Intelliconnect, back to 1985, Checkpoint back to 1950, and the Federal Research Library, which has some PLRs back into the 1940s.
I'm not sure how to get other pre-'54 PLRs. Two possibilities: call the IRS Library (202-622-8050), or file a FOIA request with the IRS.
You can find cases citing a particular PLR using KeyCite on Westlaw.
Publications: You can get current IRS publications for free from the IRS Web site. In addition, CCH publishes Pubs in a loosef services called IRS Publications, and they're included in the Federal Research Library, Checkpoint and the CCH Standard Federal Tax Reporter on Intelliconnect.
Old Pubs are on Lexis and Westlaw back to 1984.
To verify information about old Pubs (or maybe to get copies), try the IRS Publications Branch at 202-622-5210. If that fails, try the IRS library (202-622-8050).
Regulations: IRS regs are published first in the Federal Register and subsequently compiled in the CFR (see "Federal Register" and "Code of Federal Regulations"). IRS Regs are also available on Lexis, Westlaw, the Federal Research Library and the the CCH Standard Federal Tax Reporter on Intelliconnect. Comments on proposed regulations are available on Federal Research Library, Lexis (TAXANA;TNT) and Westlaw (TNT). For more sources, see "Internal Revenue Code and Regulations."
Revenue Rulings and Procedures: Revenue Rulings and Revenue Procedures are published in the CBs and IRBs discussed above in the "Bulletins" section of this entry. In addition, Revenue Rulings are posted free on Legal bitstream back to 1954 and Taxlinks back to 1955, while Revenue Procedures are posted free on Legal bitstream back to 1955.
For broad coverage and better searching, Revenue Rulings and Procedures are searchable in the Federal Research Library back to 1954 and 1955, respectively, while Westlaw offers separate databases for Rulings (FTX-RR) and Procedures (FTX-RP). Westlaw provides Rulings and Procedures from 1954 in its Bulletins databases (see above). Versuslaw has IRS Rulings back to 1953.
Note: The form for pulling Ruling and Procedures from Lexis are "revrul 72-35" and "revproc 86-22", respectively.
To find cases discussing and interpreting a particular ruling or procedure, run the citation through KeyCite on Westlaw.
Technical Advice Memoranda: TAMs are drafted by the IRS National Office in response to questions from IRS personnel. They are posted on the IRS Web site back to January, 1997 in the Electronic Reading Room. TAMs are also available on Westlaw (FTX-TM), the Federal Research Library, Checkpoint and Lexis.
You can find cases citing a particular TAM using KeyCite on Westlaw.
Treasury Department Orders: Are published in the IRBs and CBs discussed above in this entry. In addition, they are available in the FTX-TDO database on Westlaw.
TRULY TOUGH QUESTIONS:
If you are stuck on a question about IRS materials, and you've exhausted all other reasonable options, call the IRS library (202-622-8050). I've found their librarians to be knowledgeable and very helpful.