Nonfiction books are literature based on facts and information about the real world. They cover a wide range of topics, including history, science, biography, business, cooking, health and fitness, pets, crafts, home decorating, languages, travel, home improvement, religion, art and music, self-help, true crime, and humor. Nonfiction books aim to present topics objectively based on historical, scientific, and empirical information, although some non-fiction ranges into more subjective territory, including sincerely held opinions on real-world topics. Nonfiction is prose writing that sounds like everyday speech and is not written in meter, like poetry. Examples of nonfiction works include expository, argumentative, functional, and opinion pieces, essays on art or literature, biographies, memoirs, journalism, and historical, scientific, technical, or economic writings. Nonfiction books are an essential approach to narrative storytelling and are often contrasted with narrative fiction, which is largely populated by imaginary characters and events.