The Art of Doing Science and Engineering
How to Solve It
Anything by Tufte
The Millionaire Fastlane (terrible title, brilliant book)
and since I'm in VR, I have to mention Ready Player One.
Here's an odd one of mine:
The Trachtenberg Speed System of Basic Mathematics
I checked this out from the Scottsdale library when I was 11. I'd learned all the usual algorithms to multiply and divide and do basic arithmetic, but like most kids, I assumed that those were the only ways to do those things - that the steps we learned were truly fundamental and the one and only way to get the result.
Then I read Trachtenberg and learned that there were other procedures you could use to get the very same results. The techniques we'd learned were not the only ones!
Oh, there were tradeoffs - you might have to remember more stuff and more special cases - but once you had those down you could zip right through a calculation that would have taken a long time otherwise.
So that's how I learned that there was more than one way to do it.
Funnily, after applying the Trachtenberg system for many years, I came to realize the traditional methods were pretty good too.
First, I became less of an asshole.
Second, I learned to not work for assholes.
Third, I learned that if I do choose to work for an asshole as a trade-off, I own that choice. I'm never trapped.
My job satisfaction has gone way up for those three improvements.