Books for Advanced Players

[Mikey]

I was wondering.
There is a book out there called Hold'em Poker for Advanced PLayers by David Sklansky.

I don't think of the book as Advanced as I think it is especially now since I've gotten so far from when I first got it.

Any plans for a Super Advanced Hold'em Poker or

Hold'em Poker for Expert Players.

Any books out there that go deeper??