I've been looking for a condensed matter problem book (undergrad to graduate level) to brush up on a lot of things. I have Kittel and Ashcroft & Mermin but was looking for something more along the lines of 'A Guide to Physics Problems' to get right to the heart of problem solving. I see specialised books in the fields of Atomic Physics but have never stumbled across one in solid state physics. Perhaps someone here can point me in the right direction (or even online resource). Thanks.