Good book of Chess puzzles

I am basically a beginner with only a modicum of understanding of strategy/tactics..but I would like to try to improve. 

I think the thing that keeps me from improving, is that I am not thinking ahead, and not thinking like a chess tactician... some puzzles in the "Bobby Fisher Teaches Chess" book have been helpful for me to try and be more creative in setting up forks and mating combinations. 

Since I spend a lotta time on the bus to and from work, can you help me find another good book Or source of chess puzzles to help me improve my game?

Thank you. 

The chess Tactics Workbook by Al Woolum the expanded 4th Edition is a very fun/hard chess book for beginner-master. here is a problem

Sharpen Your Tactics by Lein and Archangelsky.