It is a good book.
If you are rated 700, then your main problem is hanging pieces and pawns.
No book can help.
What helps is blunder prevention.
Always check your intended move is no blunder before you play it.
Think about your move.
Consider 3 candidate moves.
Decide which is best.
Do not play that move.
Imagine it played on the board and check it is no blunder: does not hang any piece or pawn, does not run into checkmate.
Only then play it.
My coach recommended me to study this book, so should I study it ? Some say its for 1500 otb rated players