I still have Churchill's books. Read then in High School.
I remember seeing "Serenade" somewhere, if I knew it was rare I would have grabbed it.
A couple of good books from the German perspective are:
"The Luftwaffee War Dairies" by Cajus Bekker and
"I fought you from the Skies" by Willi Heilman.
Then there are some excellent books on the Schweinfurt Raids by Martin Caiden.
I have the Luftwaffe War Diaries as well, and read Caidin's works some years ago. If you can find "Serenade", grab it.
This is my second reading of Churchill - the first time I did, starting in seventh grade, I was too young to truly understand the import of what I was reading. Thus, it was a mistake. Now the read is much more fulfilling because of an expanded knowledge base. I've also read Shelby Foote's three-volume series twice, so it's more than WWII that catches my interest. Fun comparing notes :)