This is a nicely presented book which, due to space limitations, can only give a broad overview of the properties it covers. It does not claim to be a comprehensive coverage of all National Trust buildings, but does include most of the houses and a representative selection of other properties, such as castles, watermills etc.
Generally two to three pages are devoted to each property, except for the very small ones, and this covers the history of the building itself and interesting facts connected to the building such as information on former owners, contents etc. The book is lavishly illustrated and is a substantial volume so not one which you will want to carry around on National Trust visits!
I have found it most useful in checking out properties which I am planning to visit so as to get a bit of background. If you are going to a different part of the country and are a National Trust member it is interesting to do some pre planning of NT places to visit and this book is very helpful in that respect. A very acceptable pressie for an NT member too!