Fair Use is one means by which copyrighted works can be used without obtaining permission from the copyright holder. Fair Use is limited, but flexible, and is commonly used in educational settings.

Conducting a Fair Use analysis requires weighing four factors for each individual use, and seeing if, on balance the use is a fair one. Sometimes, the use is clear-cut. Other times, it's a judgment call, and two people analyzing the same situation can come up with different outcomes. Such is the nature of Fair Use.

The four factors are:

1.     nature of the work - factual vs fictional
2.     nature of the use - educational vs for-profit
3.     amount of the work being used - small amount vs large amount
4.     effect on the market - would widespread use have a negative effect on owner’s right to receive remuneration?

 
Each use is evaluated individually by doing a Fair Use test. Legally, there is no maximum number of pages nor percentage of the whole that determines Fair Use.

Use the Fair Use Checklist from Columbia University Libraries to evaluate each particular use.

Code of Best Practices in Fair Use for Academic and Research Libraries