The book starts with pre-invasion preparations, and the odd mixture of ennui and anxiety, as the occupiers wait for the inevitable but long time coming opening of the 'second front' . Once the invasion gets underway we move around, from the German reactions to initial Allied paratroop drops, to the lethargic response of the fractured chain of command, so familiar from other accounts and the depiction in the classic Longest Day movie. Yep, Hitler really was left to slumber!
We frequently encounter characters such as Rommel, and Von Kluge, and it's interesting to note how their outward actions relate to their own inner personal feelings, the former apparent from their orders and their relations with both subordinates and superiors, the latter coming via less guarded comments to colleagues, or letters home. It's very clear that for all the vaunted fighting spirit, cutting edge materiel, and the dynamism and flexibility of auftragstaktik, the fragmented nature of the German armed forces and the complicated chain of command worked against decisive action.
But as the book proceeds, the air of inevitability builds: the Luftwaffe was by this point a spent force, the Kriegsmarine never became the equal of the Royal Navy, let alone the combined might of the UK/US maritime coalition, and the ground forces - split between the Wehrmacht, the SS, and diluted with Ostruppen, the young and the old Volksturm, etc. - were simply overwhelmed by the weight of Allied materiel.
When the fighting is near the coast and the Allied position on land is still tenuous - Rommel's idea that Germany could only win if they prevented the Allies gaining a foothold was almost certainly the best hope they had  - the Allies could still bring to bear not only their airborne superiority, a decisive factor on the Western Front from hereon in, but also the incredible weight of their naval flotilla's firepower.
As the fighting moved inland the combination of total Allied airborne dominance and the scraping-bottom dribs and drabs situation for the German's, combined with Hitler's by now totally unrealstic and detrimental 'power of the will' philosophy, which would countenance no retreats, was a certain recipe for disaster. What's most amazing is how the Germans continued to believe and obey. I suppose sheer desperation and having been locked into a victorious mindset for so long may have enabled this.
I found this terrifically informative exciting and compelling, and would highly recommend it.
The main dustjacket photo is a colourised version of a very famous image of 18 year-old Hitlerjugend panzergrenadier Otto Funk, right after a small unit action in Rots, Normandy, 1944. Here's an interesting link to a webpage where you can learn more about the series of photos this came from, Otto Funk, and the location 'then and now'. The above image, cover of a German photo-feature magazine, is from the same series
 Really a third front, with the Ostfront (and Balkans) as the first, and the north-Africa then Italian/Med as the second.
 Kluge typifies the German generals: honour bound to obey, but ultimately unable to deliver, vacillating between belief and despair. His relation to the Stauffenberg plot and the fallout from that is a fascinating and tragic sub-plot. And it's a story echoed in the actions and fate of Rommel and others as well.
 Albeit still a forlornly unrealistic one.
 Apart from the Funk cover pic, all my picture selections for this post are not in this book.