I bought a book called Official Guide to Coin Grading and Counterfeit Detection by PCGS
. This covers US coins but what I liked about it is the indepth written discussion of the elements of a coins grade and how they describe what to look of in each. Elements include wear vs incomplete strike, lustre, strike, contact marks, etc.
I would think no matter what country coinage these elements would apply. It is NOT a glossy pictured book, but does have some US examples of various grades.