All essays or compositions are comprised of paragraphs, and each paragraph should have one topic sentence. A topic sentence sums up the point of a paragraph and allows the reader to know what he or she will be reading about in that paragraph. Each topic sentence in an essay should differ from the prior topic sentence and should, in a majority of cases, be presented as the first sentence of the paragraph.

Clear topic sentences will help the reader follow your discussion and will keep your paragraphs unified.