44 / PART ONE: THE BASICS If you picked up a book and glanced at the page you’ve just read, you’d probably replace it on the shelf. Sentences have to be grouped together in paragraphs , which are indented at the beginning so the page looks more ‘reader friendly’. Paragraphs can vary in length but each paragraph deals with one topic. Within the group of sentences there should usually be a topic sentence . This is the main sentence and the content is expanded in the rest of the paragraph. The positioning of the topic sentence can vary. In the follow- ing example the topic sentence, which is underlined, opens the paragraph. It introduces the letter and the following sentences are all related to it. The first paragraph is not usually indented. Stark white and threatening, the letter lay on the brown door mat. I stared at it; my body became rigid. Although I hadn’t seen it for years, I’d have recognised my sister’s handwriting anywhere. Why was she writing to me now? In the next example, which is the second paragraph of the original passage, the opening sentences build up to the final opening of the letter in the last sentence. In this case the topic sentence, underlined, comes last. The following para- graphs are all indented. Forcing my reluctant knees to bend, I stooped down and picked it up. Holding it as carefully as if it contained a time bomb, I carried it to the kitchen and dropped it on the table. Then, turning my back on it, I picked up Deciding on a topic sentence