Try using that book in your daily games. I'm guessing you'll be leaving book and playing on your own within 10 moves as often as not, and within 20 the vast majority of the time.
Is using an opening database considered cheating?

i use that book for otb preparation ... using it in the daily would probably piss somebody off. the book goes over sidelines aswell. take a look at that book ..

Of course it covers sidelines. Any opening book will. But it simply cannot cover every possible sideline. Take the position I posted above; it simply will not cover that position even though we're only fifteen moves in.
People will not be upset if you use that book in daily chess. In fact, if that's your only opening resource, someone with a good database and an extensive library will actually be better off in the opening than you are. A lot of people use a database with millions of master-level games in their daily games; that will cover a lot more sidelines than any book.
I feel like premoves are almost cheating
But what if I have forced mate in correspondence and you're boring me?

It is common for us to do post-mortem analysis using a computer and to see what moves it has suggested and to try to learn from it. So I guess if our tutors are engines we'll start playing more like them.
This is a common misconception. However, engines don't think in the same way people do. Engines simply look at every single move. Until humans can figure out how to scan millions of positions per second, a human player will never be able to mimic an engine-like style of play.

Computers make different types of moves than humans do. The staff at chess.com can tell if you made a 1500-level human move or a 3000-level computer move. Many of the computer moves baffle even GM's, so they are easy to detect. They are not the same types of moves that humans make (even great, legendary players like Fischer, Kasparov or Morphy).
If you do so regularly then obviously. However they also have to be the right moves at the right time. It is common for us to do post-mortem analysis using a computer and to see what moves it has suggested and to try to learn from it. So I guess if our tutors are engines we'll start playing more like them.
However assuming we are not using an engine to play, we'll probably play engine-style strategies but at the wrong time
This reminds me of Magnus Carlsen's games. Lots of his moves look like computer moves. I think he uses a computer to come up with his variations, them memorizes them out to 20 moves (yes, his memory is that good). So, I believe that Fischer or Kasparov (in their prime) could have gotten him out of his book (memorization) and easily beaten him. They both had better instincts and tactics.
ya its kinda obvious when someone trades their queen for a lowly knight, and crushes you afterwards. this is true.
i still feellike mgleason should take a look at that book.