Tactics Book with explanations and problems

Hi,

I am looking for a tactics book which gives explanations to all the tactics and also which has lots of problems, ranging from easy to very hard. Has anyone got any good suggestions?

Thanks

I've been working through Weteschnik's book:

http://www.amazon.com/Chess-Tactics-Scratch-2nd-Understanding/dp/1907982027

I find it has really good explanations of how to set up things in the big picture... not just "here's a fork" but "here's how we can find and then plan to set up this fork".  There are 300 examples at the back too, ranging from pretty simple through his "five star" ones which are tough.  This is one of the better books I've come across in a while.

http://www.chesstactics.org/

The books I would recomened are: Middlegame combinations Tactical wepons of world champions. Also check out the website www.chesstempo.com where in the training tab(don't click it just hower your mouse over it) there is a option called Tactical motifs. Click it and you will get the answer to your question

Chesstempo has the explanations.

ok thanks. very helpful replies.

Another vote for Weteschnik from me.

and me.

yeah there are many good books like the one you want 

the art of combination by maxim.v blokh

what it takes to become a chess master by andrew soltis

1000 chess combinations(i don't know the name of the author)