I originally learned about the Enigma from Len Deighton's "Blood, Tears, and Folly" (http://www.amazon.com/Blood-Tears-Folly-Objective-World/dp/0...). In it he doesn't even mention Turning, and gives full credit to the Polish code-breakers. I thought the recent focus on Turning was more of a "Hollywoodazation" of the event than anything else.