I've been steering clear from comments so far, but since Jojo asks...
The perfect/best book?
It doesn't exist. Everybody's style of learning is different, and an individual's depth of experience also comes into play. There won't be a single book to rule them all.
That being said I try to read as much poker theory in as many books and magazines that I can get my hands on.
You can get strong theory and some of the math from Sklansky if you manage to stay awake through it. There are some people that can take numbers delivered through a book, I have to keep at it.
Articles from any pro may have some value, even if you read it and disagree you’re participating in your own learning. The point is to be exposed to as many situations either through play or vicariously through other’s poker scribblings. Listen to everyone, even the donks. If you can identify with why their method is weak, and explain it logically, you’ve gained something by reading what they’ve written.
For me to learn effectively I need to participate in discussion and receive feedback. Hopefully I’ll recall the good messages and not remember it for bad advice the next time I find myself in a similar situation

I’ve read a few books, including Super System and Theory of poker. Both had at least some merit and have; won a pot for me that I usually wouldn’t have and/or helped me get away from one that I would have played incorrectly. Either of those merits a ‘buy’ to me.
My advice is buy them all read them all, and go back to the often. Talk strategy to everyone you can, not at the table

, and stay with it.
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So, my answer is... there is no 'best no-limit cashgame book'.