Music history is littered with great thinkers, bringing a broad range of unique perspectives to the exploration of the art form. But a name you might not expect to see on that list is Sir Isaac Newton, president of the Royal Society and leader of the Scientific Revolution. And for good reason: he pretty much never wrote about music. It wasn't an area particularly that interested him, and he rarely if ever listened to music for fun. But as a part of his well-rounded education, he did learn music *theory*, and a nearly-forgotten notebook from his college years tells us a lot about how he understood the subtle art of sound.