When a group of scientists discusses models, they can expect some shared understanding of what this term means. When the general public hears the word models, it conjures up a range of images, from fashion icons to miniature trains, but rarely the kind of internally consistent formalised reasoning meant by scientists. In this chapter we show that models and modelling are more familiar and less arcane than people think. All humans use models, consciously or unconsciously, because models are the guidebooks that help us navigate the world we live in. However, as the modern world has become more interconnected and complex, the intuitive models that have served us for millennia are increasingly guidebooks to the past, and of declining value. Her...