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Tax Law

This guide is designed to help you find laws and information on tax law issues (mostly U.S. federal but some state and non-U.S. resources).

Getting Started

Research Overview

This guide is designed to help you find laws and information on tax law issues. Although it focuses on U.S. federal tax law, it does include some information on state and local tax matters as well as some non-U.S. tax information. 

The purpose of this guide is to introduce you to a number of useful tax law resources and get you started in the right direction. Legal research requires analysis and synthesis of information, and no one resource will likely provide complete information or data on any given topic.

For many of these databases, you will need to use your Harvard Key to authenticate yourself as a Harvard or HLS-affiliate.  For others, you may need to register and create an account to gain access (e.g., Lexis, Westlaw, and Bloomberg Law).  If you have any trouble accessing a database, please contact the library.

Specialized Tax Research Platforms & Resources

Westlaw, Lexis Advance, and Bloomberg Law all offer Practice Centers (or Practice Areas) that focus on Tax Law matters.


In addition, you should consider looking at the following tax-centric research platforms/resources:

Learning Tax Research

Below are some books that can help you better understand how Tax Law resources are organized and where you can find them.

Primary Sources/Federal Government Resources

Federal Tax Statutes

Federal Legislative History

In addition to standard legislative history resources (e.g., ProQuest Congressional's Legislative Insight for federal legislative history), you should check out:

Federal Tax Regulations

NOTE: Don't assume you will always find regulations under the same CFR Title number as the USC Title number for the authorizing statute. This is the case for some areas of law, including tax matters ("Title 26" for both the USC and the CFR). When the CFR was first created, it followed the USC's organizational structure. However, the two collections later diverged. See here for more information.


The Federal Register is where all federal agency rules and regulations are initially published (when first proposed -- perhaps re-proposed -- and later finalized). Agencies are required to include summaries of proposed regulations and the public comments received thereon, as well as an agency's reaction to the public comments when finalizing a regulation. This is typically done in the preamble to a finalized or re-proposed regulation.

The preamble information published in the Federal Register is the primary published source for a regulation or rule's "regulatory history" and one of the few ways to determine "regulatory intent." 


Other IRS Guidance

NOTE: IRS guidance/rulings requested by individual taxpayers (e.g., Private Letter Rulings, Technical Advice Memoranda, and Chief Counsel Advice) may not be relied upon by others and are not published in the IRB.

Nevertheless, they may provide insight regarding the IRS's views on various matters. They may be obtained by the public via FOIA requests and can often be found on the (see the IRS's FOIA Library) or by using commercial legal research platforms.

The IRS website is not the easiest site to navigate but it does contain a lot of useful information. For example:

U.S. Tax Court

U.S. Department of Justice -- Tax Division

Secondary Sources

Treatises, Books, and Reporters

Look under "Secondary Sources" (or "Secondary Materials") in the Tax Practice Center/Area of a legal research platform to find treatises and other materials about tax-related topics. Below are some specific titles:

Study Aids

Databases for Finding Tax-Related Scholarship (and Other Types of Articles)

In addition to searching for tax-related law reviews and journals using Westlaw, Lexis Advance, or Bloomberg Law you can try these alternatives:

Specific Tax Journals

Current Awareness

Tax News

Tax Policy Think Tanks

Tax Blogs

State Tax Resources

Online Resources

Individual state tax agencies can provide a lot of helpful state tax information. The Federation of Tax Administrators provides a list of links to the websites for state tax agencies.

You can also find a number of state-specific tax resources if you look for state law content on Lexis Advance or Westlaw.

See below for more useful links:

Other Resources

Other Research Guides

Below are some other Research Guides you may find useful, depending on your area of research:

NOTE: When using a research guide prepared by a different library, the links may not work for you. However, if you find a title of interest, you may be able to locate it in our collection by using HOLLIS (Harvard's Library Catalog). If not, we may be able to obtain the resource through BorrowDirect or Interlibrary Loan.

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