Individual users and organizations must get permission to distribute or republish copyrighted works. The Copyright Clearance Center is one organization that faciliates the permissions process. See also, Copyright@CUNY, How to Get Permission.
Fair use allows the use or copying of a limited amount of copyrighted materials as long as the following four conditions are met:
1. the purpose is educational, not commercial, and the audience is limited to a person, a class or a group of students, i.e. not public. Allowed purposes include teaching, news reporting, criticism, scholarship and research (17 USC 107);
2. the work is published, and not meant to be consumed by one user (like a workbook);
3. a relatively small amount of a work is copied (e.g., not the whole book);
4. the material is not easily purchased at a reasonable price.
An article on fair use in the academic environment appears in a recent issue of the Chronicle of Higher Education : "Pushing back against legal threats by pushing fair use forward" (Jeffrey R. Young, May 29. 2011).