Hello Volker,
As I've said in several other threads, this is a superb series of books. If you're someone (as I suspect

) who likes to go searching for old airfields and the graves of airmen of all nationalities, this is a WONDERFUL series.
Or, if you're just interested in great stories of aerial engagements and actions, with lots of photos and maps you cannot find elsewhere, it's also a great series!!
I highly recommend all of them.
Greg