The Narrow Road draws its title from Oku no Hosomichi (The Narrow Road to the Interior), the famous travel diary of Matsuo Basho as he journeyed into northern Japan. My aim is to follow a similar wandering journey, but instead travelling into the abstract highlands of pure mathematics, pausing to admire the beauty and sights along the way, much as Basho did. That means we have a long way to travel: from the basics of abstract or pure mathematics, through topology, manifolds, group theory and abstract algebra, category theory, and more. There may well be some detours along the way as well. It is going to take a long time to get to where we are going, but along the way we’ll see plenty of things that make the trip worthwhile. Indeed, as is so often the case, the journey means more than the destination.