Hi, folks. I suffered through college math all the way through differential equations, and I never really "got" it. I just memorized the steps and, when exam time rolled around, hoped I could remember which procedure went with which problem. The light finally came on in grad school, and _Principia_ was the switch. Reading the _Principia_ let me get underneath formal calculus and imbued it with a sense of wonder and soul. To see the theory set out step-by-step, to follow with Newton as he envisioned a new way of painting the world, gave me the ability to internalize the calculus, to say, finally, "Yes, that's intuitively right." I wish I'd read the _Principia_ much earlier in my education. It would have saved me a lot of pain.