Postcolonialism theory examines the oppression experienced by colonized peoples and societies. It addresses factors like political, economic, social, cultural and psychological oppression imposed by colonial powers. Major postcolonial theorists include Edward Said, Gayatri Spivak, and Frantz Fanon. They analyzed how colonizers imposed their values on colonized groups, influenced identities, and resisted colonial rule. Postcolonial criticism now examines themes like hybridity, exile, and double consciousness in former colonies' literature and culture.