So, compared with some writing on WWII, this is a bit patchy from the scholarly apparatus point of view. But, for me, as someone with very limited knowledge of this aspect of the war, this was a fascinating and compelling read. A glossary, bibliography, and notes on sources would all improve the book. But in its favour, its use of maps and photographs help make it more vivid and easier to follow than many other books in the military history camp.
Overall I'd definitely recommend this to those with an interest in the period.
Having also recently read about a similar instance of attack as constantly shifting rearguard action in Jeffrey Plowman's Greece, 1941, quite how 'we'* won the war, getting off to such a shaky and badly managed start, is a mystery. As Saunders observes on p.101: 'all-arms tactics were almost non-existent in the British Army of 1940.' He also notes that this remained true even as late save the Normandy campaign, post D-Day!
* Well, with the combined weight of industry and numbers that first Russia, then the U.S., and not forgetting our own ability to draw on the manpower resources of the Commonwealth, that 'we' becomes significantly larger, and the outcome less mysterious.