Can I use a quote in my book without getting permission?

It depends. Under ‘fair use’ some copyright protected material can be used without permission; however, there are no clear-cut rules, only guidelines and factors to be considered. ‘Fair use’ is not a right, only a defense.

There are four factors that determine fair use:

1. The purpose and character of the use, including potential gains for commercial or non-profit;
2. The nature of the original copyrighted work;
3. The proportion or percentage of the copyrighted material in relation to the work as a whole; and
4. The potential effect on the value of the copyrighted material.

There is no definite rule regarding the number of lines or words that can be used without permission. Also, simply citing the source is not an alternate for obtaining permission to use the material. In general, if you are quoting a few lines within a long book, you will probably be protected under ‘fair use’. However, if you are concerned, and to be on the safe side, always consult with a qualified legal advisor before using copyrighted materials in your book unless you have a written permission.

Works that are considered to be ‘in the public domain’, works whose copyright has expired, been forfeited, or inapplicable, can be used freely without permission. However, determining whether a work is truly in public domain is tricky due to publication of new versions, copyright protection outside the U.S., and protection under alternative laws.