Mcse Books

I am currently studying for the MCSE and have the Exam Cram books which are excellent for telling me HOW to do something, but not too hot on the WHY and WHEN. Does anybody have any recommendations for an exam book or networking books that would give me the WHY and WHEN to use the various functions questioned on the exams. I can memorize the HOW for the test, but would also like to know WHEN and WHY is the best choice to use. I use this on a day to day basis, so I am getting the hands on necessary, but most often I do it because “that is the way we do it here” not because I really understand.