I've been doing the tactics problems at jrobichess.com and shredderchess.com pretty regularly, and recently added chesstempo.com. I find I'm much better at attacking tactics than defensive tactics: that is, I can solve "Find mate in X"-type problems at a much higher level than "Avoid mate"-type problems, even when the calculations are basically the same. I know how to deploy various attacking ideas, but I haven't learned to see them coming and defend against them. What are some resources I could use to improve this side of my tactical play? Is there a site like the above that stresses defensive tactics, or where you can select specifically defensive problems?
I enjoyed Andy Soltis' The Art of Defense in Chess. It was all about finding hidden resources.
Remarkably, this book is available electronically for no cost, and legally I assume. Here are a few links.
The are many online guides about chess defensive strategies, but there seem to fewer products. Books, as the other post mentioned, are also useful.
These are some links.