Plenty of biographies. "The Rocket Team" by Frederick Ordway is a good one. And, as much as I might begrudge it, the Wikipedia entry is probably pretty fair. Plus one of Albert Speer's books details the manner in which Heinrich Himmler maneuvered to bring the V-2 program under his personal control. It was remarkable how Hitler maintained power by deliberately inciting internecine bureaucratic conflict. Kept his subordinates so busy struggling with each other, they had no time or ability to organize against him.