The title promises a bit more than this book delivers, somehow: I expected one of those books with a thesis along the lines of "the war was really one by X, Y, and Z". But the author is much too fair-minded, analytical and circumspect to get carried away with anything like that, so he ends up pointing out a series of innovations that moved things along in the allies favor, but it ends up feeling a bit anticlimactic.
The book is quite thorough, and interesting, and does take a unique approach to WWII history in that it examines what technology enabled the allies to win. Examples include radar small enough to be carried on board airplanes, and other anti-submarine systems, long range fighters, and the technology and, above all, organizational skills necessary to
carry out amphibious landings both in Europe (operation Overlord), and
in the Pacific theater.
Interestingly, he discounts, to some degree, the role of the code breakers, who have came out of obscurity in recent years. He agrees that they were helpful, but perhaps not really decisive, compared to improved weapons systems that, for instance, actually sank German submarines.
If you've never read any history of this war, there are more comprehensive books, but I enjoyed the focus and detail on a specific aspect of it. If you're not interested in the details of WWII, skip it.
When comparing this conflict to anything relatively recent, the amount of people who lost their lives is truly staggering and horrifying, and bears thinking about in the hopes that nothing like it ever happens again.