IRS Publications are officially published by the IRS. In this instance, "Publication" is a specific term, and does not apply to all IRS publications in a general sense. They are specifically numbered as Publications. For example, Publication 15 is the Employer's Tax Guide.
"IRS Publications explain the law in plain language for taxpayers and their advisors. They typically highlight changes in the law, provide examples illustrating Service positions, and include worksheets" (IRM 18.104.22.168.8).
"Publications are nonbinding on the Service and do not necessarily cover all positions for a given issue. While a good source of general information, publications should not be cited to sustain a position" (IRM 22.214.171.124.8).
They do not constitute substantial authority for purposes of the substantial understatement penalty.
Westlaw contains current publications and retired publications from 1984 - 2014. The scope note says "documents have been edited by the IRS to eliminate references to graphics that are not displayable, and reformatted from the original IRS design for display purposes on WESTLAW. No substantive changes have been made to the publications."