Good book on calculation but not any book!

Don't buy any books yet.  Just do Stoyko exercises -- like 1,000 of them. 

There is no real magic to calculation.  It is a skill that CAN be improved with hard work.  The steps to calculation are straight forward - pick moves that look interesting, calculate each one, evaluate the final position, and choose the move with the best evaluation.  

The process is simple, but there are PLENTY of ways to make mistakes.  That is where the books will come in useful.  But before you know what your mistakes are, the books will be purely hypothetical to you.

I have done tons of these exercises and can give you tips, if you'd like.  My blog goes into extensive detail on how to do them (books of positions, how to use clocks, even what paper to use).  http://ultimaterank.blogspot.com/2014/10/about-stoyko-exercises.html 

The key for me was keeping an error log.  Here's a copy of my early error log:

I've slowed down a bit but I still do several Stoyko positions every weekend, and even started a club here on chess.com to share positions/calculations.