The author goes into detail about war preparation dealing with gas attacks, air raids and food. He also shows how overwhelmed local government were when they were tasked with setting up shelters, food distribution and firefighting services. It is easy today in 2017 to forget that a village or town may not had any fire fighting equipment in 1938.
The plans that he looks at were often designed in 1917 and barely dusted off. There was always the expectation that the next war would not occur without a decades amount of warning. Instead of 10 years the British had only from Oct 1938 to Sep 1939 to complete the preparations, which were often not even started yet.
Lastly he goes into a great deal of detail of how the British primary plans were always to just "muddle through". It is uncertain if government agencies just thought war was never going to happen, or if if they thought is was someone else's job to start and finish the projects. That changed with Munich. It was for the best, that plans were given some time to complete before September 1939 and even into the winter of the Phony War. Without that time there would not have been either Chain Home Radar Stations or the Hurricane and Spitfire. Just think of the Battle of Britain with the Hawker Hart and the Gloucester Gladiator.
As for a recommendation, I give this book five stars if you are interested in Sea Lion or inter-war military history. As it covers no battles and ends with the start of the war, it has very little action other than buearacratic and great great what-ifs. Enjoy.