This document summarizes key ideas from two works: Frank's "The Development of Underdevelopment" and Dos Santos' "The Structure of Dependency". Frank argues that modernization theory, which views underdevelopment as a natural phase, is deficient because it ignores how colonialism altered development paths in the Third World. Underdevelopment was intentionally created through exploiting resources and transferring economic surplus to Western nations. Dos Santos identifies three historical forms of dependency - colonial, financial-industrial, technological-industrial - and how they structurally limit industrial development and reproduce inequality in dependent nations under foreign capital's control.