The prologue is great:
"Considering how many fools can calculate, it is surprising that it should be thought either a difficult or a tedious task for any other fool to learn how to master the same tricks.
Some calculus-tricks are quite easy. Some are enormously difficult. The fools who write the textbooks of advanced mathematics (and they are mostly clever fools) seldom take the trouble to show you how easy the easy calculations are. On the contrary, they seem to desire to impress you with their tremendous cleverness by going about it in the most difficult way.
Being myself a remarkably stupid fellow, I have had to unteach myself the difficulties, and now beg to present to my fellow fools the parts that are not hard. Master these thoroughly, and the rest will follow. What one fool can do, another can."
http://www.amazon.com/Calculus-Easy-Way-Douglas-Downing/prod...
I only managed to satisfy degree requirements by taking 'logic' (a philosophy class) instead of calculus. I was warned off trying this route by a few people though, as it was "hard". I'd been hobby programming for... 10 years at that point - there's little about 'logic' that could possibly be 'hard' in a logic 101 class, so I passed by doing something I was naturally good at. I simply couldn't afford (financially) taking calculus another 2-3 times to keep trying to pass.
It's still a sore point even now... 20+ years later, and a source of secret (perhaps not so secret now that I post this!) shame. :(
I'd never even had to try at anything (except music, perhaps) until well in to high school, at which point I'd mostly just given up. I scored in the top 2% of the ACT test (back when it was scored differently, in the 80s), and I'm not actually 100% sure I finished all the questions - I know I didn't study for it, nor was I particularly well rested. Yeah, as someone else wrote, schools are simply not oriented towards helping 'gifted' students, assuming that they're already 'ahead' of others, and seem to be left on their own - I know I was.