The "Natural History" is encyclopaedic in scope, but its format is unlike a modern encyclopaedia. However, it does have structure: Pliny uses Aristotle's division of nature (animal, vegetable, mineral) to recreate the natural world in literary form. Rather than presenting compartmentalised, stand-alone entries arranged alphabetically, Pliny's ordered natural landscape is a coherent whole, offering the reader a guided tour: "a brief excursion under our direction among the whole of the works of nature ..." The work is unified but varied: "My subject is the world of nature ... or in other words, life," he tells Titus.