The book is meant to be simple problems from amateur blitz games which show common tactical mistakes for people in this rating range. The book does exactly what it promises. For your level (1721 in blitz is very good) you would need a more difficult book like Learn Chess Tactics by John Nunn.
Lots of books get good reviews but I don't purchase them because they do not seem to be right for my level.
I tore through this book ("Tactics Time!" by Brennan and Carson) in no time, and I am absolutely amazed that it's gotten so many positive reviews. Is it me, or does it seem like the problems are well below 1200 strength?
What's your experience with the book been?