This document defines paragraphs and discusses their key characteristics and structures. It notes that a paragraph is a group of related sentences dealing with one central idea. For effectiveness, a paragraph must demonstrate unity around a controlling idea, coherence through logical connections between sentences, and complete development of the topic. Different types of paragraphs are described, including descriptive, narrative, and expository paragraphs, which can be used for division/classification, illustration, cause/effect, comparison, contrast, and definition. Proper paragraph structure includes a topic sentence, body, and concluding sentence.