Thinkers such as Aristotle, Plato, and Parmenides have shaped the way we see the world, and it is their original conception of philosophy which has placed topics such as logic, metaphysics, ethics, and ontology at the heart of philosophical debates for centuries. Miriam Leonard not only explores the central theories of their works, but also gives some sense of the messy process of abstraction, where written texts get transformed into timeless ideals. She looks at how simple phrases such as “in what way?” or “there is” are turned into the language of philosophy. Taking passages from Heraclitus, Parmenides, Lucretius, and Cicero as well as Plato and Aristotle, this guide provides an insight into the influence of its texts on the later history of ideas.