Despite its small size, the book covers quite a vast area.
It certainly does the job its intended to and provides a well documented account of one of Hitler's most efficient war weapon.
the structures are simply monumental with roof slab reaching 7m thickness in some places. It is also quite amazing to see this bunker intact after heavy bombardments from the RAF or USAAF and see the lunar landscape surrounding.
Another surprising part was to read about Uboats acting in Singapour, Penang or even Kobe. One Uboat is said to have come back from the far east to its base in France just in time for the armistice.
Some of the colour plate as pointed out in other reviews could have easily been ommited or with a smaller size : e.g. first one for "long range defense"
Some other are quite stunning and plunge you back 50yrs in the past.
Otherwise the book could seem a bit repetitive as the author review all the bases giving length, width, etc. of each structures which makes it a heavy reading sometimes.
Why not a page dedicated to a table summarising of these facts? Easier to read and easily skipped if one not interested in preciste technical details.
In the end, despite few minus, a very good book that does a decent job.