The document discusses Binding Theory, which was proposed by Noam Chomsky. Binding Theory explores the principles governing the structural relationships between pronouns, anaphors, and their antecedents within a sentence. It defines key terms like pronouns, anaphors, antecedents, and R-expressions. It also discusses concepts like coindexation, binding domains, and the three principles of Binding Theory - Principle A governing anaphor binding, Principle B governing pronoun binding, and Principle C governing R-expression binding. Overall, the document provides an overview of Binding Theory, its key components, and how different types of referring expressions are bound or free within a sentence based on Binding Theory.