Nothing about the prose seemed compelling though there were points of interest that are notable in this work. Keegan took classic incidents in war where intelligence proved crucial for the action--Napoleonic wars, Jackson in the Shenandoah Valley, the invention of the wireless, Crete in WW II, Midway, the Atlantic War in WW II, and German advances late in WW II--then, he notes the limitation of intelligence and how it did not prove to be the crucial factor in the outcome. On Crete, for example, the British had detailed intelligence and yet, lost the engagement. He makes the point that force predominates over intelligence, advance knowledge or inside information does not always determine the outcome. More importantly, in the section on intelligence after 1945, he points out that intelligence can not ascertain the appropriate course of action. Saddam proved to be exceptionally obtuse and the Coalition acted on the limited intelligence available to them. The knowledge of intelligence can only go so far. Force is required although the popularizers of intelligence, mostly from novels, gives us the impression that intelligence reveals all. It does not. The key to Keegan's work, as a pre-eminent military historian, is in the subtitle: "The value--and limitations--of what the military can learn about the enemy."

I'd broadly agree with the review by ben_a -- this isn't Keegan at his best, and whilst the central argument ("intelligence is useful, but can't be decisive in itself") is well-presented, there's a lot of padding in the case studies. Some of the chapters show evidence of recycling of material that he has used elsewhere -- there are sloppy edits, and unusual amounts of repetition within the chapters.
The chapter on the V1 and V2 programme, in particular, looks very cobbled-together, and seems to go round in circles a few times.
It also looks as though the sub-title ("...from Napoleon to Al-Qaeda"), presumably imposed by the publisher, has pushed Keegan into writing speculatively about the "war on terror", a role he clearly isn't very comfortable with. (To add insult to injury, I discovered, far too late to think about returning it, that my copy had been bound with two copies of the second set of plates and none of the first set!)

It's probably worth reading this book as an antidote to the romantic idea of espionage as a war-winning activity, but it's a shame the author wasn't given time to do the job properly. ( )

I listened to this in audio form, read by a narrator with one of those aged British voices that always seems to accompany all things martial. Author John Keegan traces military intelligence through history. There’s a definite Anglo centric tendency, with a great deal of attention paid to Admiral Nelson and pals. Keegan makes the case that while the public and policymakers alike see military intelligence as a pursuit of supreme importance, the cold reality of war is that might nearly always wins regardless of what each side knows. Oh, and luck plays a large role, too. Military intelligence plays, at best, a secondary role. Keegan’s arguments may or may not be compelling. Fans of military history or those interested in the theory behind espionage, though, will likely find the exploration of his chosen case studies interesting.

This book examines how effective intelligence is in determining the outcome of battles and military campaigns. The writing is clear and effective, as are his arguments showing the strengths and weaknesses of intelligence and its ever changing roles.

The history is fascinating. He starts with Nelson playing hide and seek witth Napoleon's Egyptian assault fleet. Then he shows how Stonewall Jackson uses local knowledge and manoeuvre to tie up a large part of the Union Army in the Shenandoah Valley. Then he uses the destruction of von Spees cruiser force in World War I to explain the development and early uses of wireless communications. In the Airborne German capture of Crete in the Seconf World War, it is demonstrated that even great intelligence without proper analysis can lose a battle. Midway was one of the great strategic intelligence coups of the twentieth century, but he shows how the tactical victory depended more on luck and chance than good information. The Battle of the Atlantic and the role of the wizards of Bletchley and their German opponents is carefully explained; it is shown that the battle would still have been won by the Allies, and why. Then there was the knowledge and scientific grandstanding that made the impacts of the V-1 cruise missile and the V-2 IRBM so much greater towards the end of the war; if the Germans had a nuclear weapon with these devices, he thinks Germany might have won. In the last two chapters the development and uses and misuses of intelligence up to modern times is discussed, followed by a detailed analysis of strategic and tactical intelligence.

The conclusions are well considered and do not match the popular wisdom. ( )

All Keegan is good, but this is not his best. The case studies, while fascinating, and replete with Keegan's usual exquisite selection of telling details, are longer than their illustrative purpose requires. I would have preferred shorter cases, more of them, and more synthesis. And, very rare for Keegan, there is evidence of writing in haste. The basic hypothesis -- intelligence as a uninformly insufficient condition for victory -- is unimpeachable, but also obvious. ( )