The most recent print copy can be found in our Reference collection with the call number: JK421 .A3. Older copies are available in the Government Documents collection under the Superintendent of Documents (SuDoc) Number: AE 2.108/2:.
However, this is also available online, and the most recent copy can be found at the Government Manual website (http://www.usgovernmentmanual.gov).
The Manual includes text of the Constitution and Declaration of Independence. You can use this resource to learn about the 3 branches of the federal government as well as the divisions within each branch. There is even a section that explains how agencies have changed over time through name changes and moving within the government structure.
If you would like to look at past government manuals online, they can be found at the Government Printing Office's FDsys (Federal Digital System) website. Currently, they have the manuals back to 1995-96.
Take advantage of this resource just for the general information, to learn more about a specific part of the federal government, or to supplement your class research!