From John Ferris’ official history of GCHQ and its predecessors. One of the rare subject-specific histories that makes a case for downplaying the importance of its subject.

There are some interesting sections to that book but it was very dry and I'm afraid it's sat on my bookshelf unfinished at the moment.

Ferris makes the point that by the time Ultra sigint matured, the war had largely become one of vast armies hammering away at one another, and there were limitations to how much even the best intel could influence such an attritional conflict.

The recent historiography in my intelligence history subject area does the same thing, oddly enough. I count myself in that trend, too. I guess it's Ferris rubbing off on me.

I don’t think it’s downplaying. I think it’s qualifying it. It is an incredible force enhancer which allows the Alllies to pursue various strategies that were more economical than in the FWW when they did not possess the same potent weapons system.

Definitely an interesting perspective from someone writing about a subject. I cannot count the number of times I have read a subject-specific history and ended with the general feeling that the topic was not nearly as important as the author portrayed it as.

Second-year War Studies included a course about intelligence in war, and mostly what I remember about it is even if you 'know' something from intelligence sources, that doesn't necessarily mean you can do anything with that information.