I've tried searching online and the best I've found is separate books for individual regions like the UK. I'd like a source which compares and contrasts different castle architectures and classifies them into groups. A level lower than just ancient, medieval and modern. Thanks in advance!
A chronicle history of forts and fortresses by Martin Brice
It covers different types of forts spanning from the ancient world to medieval times to the industrial era. It seems to be more of an introductory book as it briefly covers many types of castles and only goes in detail on a few specific types. It does describe how each type of castle fits into the contemporary styles of warfare.
Disclaimer: I am not a historian, just had an interest in castles many years ago.