What is the best chess book on tactics?

I am rated around 1250 and have played at that level for a looong time. Please recommend a book or series that will help advance my game, especially around tactics. Thanks!

Chess Tactics for Champions by Susan Polgar for basic tactical motifs.  Go through the book three or four times or until you can spot most of the tactics in the book in a second or two.

How to Beat Your Dad at Chess by Murray Chandler for common mating patterns.

1001 Winning Chess Sacrifices and Combinations and 1001 Brilliant Ways to Checkmate by Fred Reinfeld.  Get the algebraic editions that were recently released.

Last but not least, CT-Art software is highly recommended for drilling on tactics.

Forgot to mention a book I recently picked up:

The Chess Tactics Detection Workbook by Schleputz & Emms.  You play through games originally played by 1100-1700 rated players and look for tactics that they missed.  This approach not only helps you build your tactical skills, but helps you develop a thought process where you think about the possibilities for both sides rather than just your own.  Moreover, since no clues are given as to on which move(s) the tactics were missed, you get into the habit of looking for tactics on every move.

A very wordy book about tactics is available for free online. It teaches not only the tactic, but mainly the thought process to find out or to set up a tactic. With many many examples full of explanations. The only "downside" is that it doesn't include exercises but one can treat the diagrams as exercises before reading the text.