This article provides a comprehensive overview of the basic notions of Information Structure (IS), including Focus, Givenness, and Topic. It begins by characterizing IS within a communicative model of Common Ground (CG), distinguishing between CG content and CG management. The paper then defines and discusses the concepts of Focus, which indicates alternatives, Givenness, which indicates that a denotation is already present in the CG, and Topic, which specifies what a statement is about. Additionally, it introduces the notion of Delimitation, which encompasses contrastive topics and frame setters, indicating that the current conversational move does not fully satisfy the local communicative needs. The article also explores the pragmatic and semantic uses of focus, highlighting how it can affect the truth-conditional content of the CG. It concludes by examining the representation formats for focus and the interaction between focus and givenness.This article provides a comprehensive overview of the basic notions of Information Structure (IS), including Focus, Givenness, and Topic. It begins by characterizing IS within a communicative model of Common Ground (CG), distinguishing between CG content and CG management. The paper then defines and discusses the concepts of Focus, which indicates alternatives, Givenness, which indicates that a denotation is already present in the CG, and Topic, which specifies what a statement is about. Additionally, it introduces the notion of Delimitation, which encompasses contrastive topics and frame setters, indicating that the current conversational move does not fully satisfy the local communicative needs. The article also explores the pragmatic and semantic uses of focus, highlighting how it can affect the truth-conditional content of the CG. It concludes by examining the representation formats for focus and the interaction between focus and givenness.