Not sure on availability in Germany, but there's a decent 6 part series called "Moon Machines" - aired originally on the Discovery Channel. It covers the major components of Apollo and Saturn V. It's filled with interviews of the engineers, discusses major problems, and the solutions thereto.
ETA: I think this is it on Amazon.
ETA2: The six parts are:
Saturn V Rocket
Command Module
Navigation Computer
Lunar Module
Space Suit
Lunar Rover