Professor Holger Herwig’s Luxury Fleet is the single best book on the Imperial German navy that I’ve read. It manages to be both detailed and fun, going into political squabbles and technical details while remaining easy to read. Reading it really gets you a feel for the “Luxury Fleet”, or “Tirpitz’s Folly”.
It’s great to read this alongside Andrew Gordon’s The Rules of the Game, an equally effective study of its adversary. But if you’re into naval history at all, this is well worth a purchase on its own.