Title VII of the Civil Rights Act of 1964 is a United States federal law that prohibits employment discrimination based on race, color, religion, sex or national origin. After the Supreme Court ruling, the Civil Rights Act of 1991 (Pub. L. 102-166) amended several sections of Title VII.
The Equal Employment Opportunity Commission (EEOC) is the federal government agency mandated under Title VII and other laws to process employment discrimination claims. A plaintiff in any lawsuit filed in federal court alleging unlawful employment discrimination must have received a letter from the EEOC granting the right to sue. This letter is obtained if the plaintiff filed a complaint with the EEOC within 180 days of the act of discrimination (or 300 days in certain cases when the complaint is filed with the state agency tasked to handle violations of state law).
Title VII prohibits employment discrimination "because of" certain reasons. While "because of" may be understood in the conversational sense, the McDonnell Douglas case was the first landmark case to define this phrase.