Using copyrighted material in your own original work may or may not violate copyright law, depending on whether the use falls under the fair use doctrine. The purpose and character of the intended use is the most important factor in determining whether a use is fair under US copyright law. If you are merely copying someone else's work verbatim, it is less likely to be considered fair use. However, if you are using limited portions of the work for purposes such as commentary, criticism, news reporting, or scholarly reports, it may be considered fair use. The nature of the copyrighted work, the amount and substantiality of the portion used, and whether the use is commercial or nonprofit are also factors that courts consider in determining whether a use is fair.