Copyright provides creators of original works with exclusive rights to copy and distribute their works. In the U.S., there are provisions related to copyright in the Constitution, federal law, and in various guidelines for education and fair use. See the Copyright Law & UST section for more information.
The purpose or character of the use; including whether such use is of a commercial nature or for nonprofit educational purposes.
The nature of the copyrighted work used.
The amount and substantiality of the work being used.
The effect of the use on markets or the value of the original work.
In general uses for educational purposes at nonprofit institutions weigh in favor of fair use. Considering factor number two, fair use favors the use of works of a factual nature more than the use of creative, artistic works. With respect to amount used, using less than an entire work, and not that portion which might be viewed as the essence of the work, will weigh more in favor of fair use. As for market effect, uses that have no impact on the market value for the original work weigh in favor of fair use. -- Policy & Principles: Fair Use, University of Minnesota Libraries.
According to the Association of Research Libraries (ARL), "...the history of fair use litigation of all kinds shows that judges return again and again to two key analytical questions:
Did the use “transform” the material taken from the copyrighted work by using it for a broadly beneficial purpose different from that of the original, or did it just repeat the work for the same intent and value as the original?
Note: a publishers' license terms may take precedence over fair use guidelines. If the publisher expressly prohibits their content from being used in certain ways, there is no need to even consider fair use.