Learning tactics from several sources: worthy books

Learning tactics from books (or online, or as ebooks) is my bread and butter for improvement. Usually the books are either a collection of positions or an exposition of the different tactical patterns. I find both approaches  are mandatory and complementary. Tactics is not just the fact of 'trying out' to calculate variations by brute force (Silman talks about how beginner insist on considering moves before analyzing position) but the fact of recognizing the patterns in the position (e.g. where is the key weakness in the position, and then calculating the tactics itself. It took me a while to understand this and it made my tactical awareness greatly improve. What are the loose pieces ? The pins ? The overloaded pieces ? This two prong study might converge to a one prong once the basic motives are understood and set in stone, only 'blind' tactics can be used to stay sharp.
the book I really like and use a lot are:

• For the pattern by pattern exercises: Chess Tactics for champions, Susan Polgar. The exercises are from 'made up' position and are reasonably simple, I find this was a great beginner book and I recommend it.
• For the set of positions: The Complete Chess workout by Richard Palliser. Position are from tournament games, alphabetically ordered by tournament name. You never know what is thrown at you, the position are realistic, and the gain are not necessary checkmate but often just the gain of a pawn. I also thoroughly recommend this book. 

I complement this with the study of  How to Beat Your Dad at Chess, Murray Chandler. This book is a one of a kind in the sense that it cover the basic mating nets. Despite the goofy title it is an extremely useful book and well worth it for beginner/intermediates. There is two more books in the same format and collection, one on tactics and one on openings, and they are good books though I have had no time for studying these.