Prejudice is an unfavorable opinion or feeling formed beforehand without knowledge or reason. The document discusses the definition and nature of prejudice, its components including affective, behavioral, and cognitive aspects, and common types such as racism, sexism, ageism, etc. It provides examples and discusses theories of prejudice formation. Research on reducing prejudice through education, mass media, and equal status contact is examined. Merton's typology of prejudice and discrimination is explained.