This document discusses topic sentences and how to write effective ones. It explains that a topic sentence should introduce the subject being described, such as a person, place, or thing, and provide an initial impression. It provides examples of topic sentences and notes that concluding sentences can either restate the topic sentence using different words, restate it and provide the writer's opinion, or restate it and convey feelings about the topic. The document emphasizes using specific, precise details in supporting sentences to help readers visualize what is being described.