I think it was in Alan Burgess' book
Seven Men at Daybreak (I can't find a copy now- I wish I'd stolen the copy from my High School library!) that I first heard Hedrich described as "the hidden pivot around which the Third Reich revolved"; the original quote came (I think) from Walter Schellenberg.
Entering that phrase into Google led me to this website:
http://kimel.net/heydrich.html