For those interested in the German development prior to the take over by the National Socialists, I would strongly suggest, Eley, Reshaping the German Right.
I am slowing getting back to it from a few weeks of reading other stuff, Golo Mann's Reflections.
Ira Glazer suggested the Eley book, thanks again... It covers the political developments between the 1880s to the 1920s when the process of reshaping was more or less complete.
What makes this subject fascinating is you get to see the process through a different society, and it manages to illuminate our own by indirection. Also it reminds the reader that at any given moment, what is going to happen is still pretty much a mystery for the immediate participants. So that each step in the direction of a nightmare it almost always possible to rationalize the impending doom away---until it is suddenly too late.
CG