Speer (the author of the "The Rise and Fall") was part of that machinery so his account should be taken with a grain of salt. Or two.
How so, David? Shirer was a journalist, not a German industrialist or military officer. He was not part of the German rearmament, the "prepare for war" part of the saying. In writing a historical account of the events of those days, he noted that the highest ranking German military officers, who had most actively prepared for war in the face of no credible threat, were quite taken aback when Hitler announced his intention to use those preparations for their intended purposes. What "grain of salt" is needed? Where was he wrong?