The primary source of information on constitutional law is of course the Constitution, as well as the case law that interprets the Constitution. The following annotated editions of the United States Constitution can be found in Gould Law Library:
United States Code Annotated (USCA), West Publishing Company
KF62.5.W4 1987 (Library 1st floor) (also available on Westlaw)
West’s Key Number System is utilized in the annotated case notes (notes of decisions).
The Constitution of the United States of America: Analysis and Interpretation, Congressional Research Service-Library of Congress
KF4527.A3 (Library 1st floor - Reference) (also available online at GPO Access)
This includes annotations of the most important Supreme Court cases. It also includes historical information, such as Supreme Court dissenting opinions and overruled decisions, as well as proposed amendments and laws that were deemed unconstitutional.