To look at this book is about two-thirds of the page size of a `normal' paperback and it is just over 100 pages long. However it covers 13 stations in that space, as follows: Paddington - Euston - St Pancras - King's Cross - Liverpool Street - Fenchurch Street - London Bridge - Cannon Street and Blackfriars (one chapter) - Waterloo - Victoria.
I really enjoyed flicking through - if I take the Euston chapter as an example, there's a full-page picture of the old Great Hall, a history of the station over about 5 pages, including a picture of the station around 1840 and another showing the infamous destroyed Arch. The final two pages of text are a description and critique of the station as a building and working space, illustrated by a photo of Robert Stephenson's statue and then two trains at the platforms in 1908.
I'm not an expert in the history of the station but the text, similar in length to a Wikipedia entry gave me enough detail without overloading. The comments on the stations were well-made and helpful, although not especially exciting.
Overall, as a book to slip into a bag or wide pocket to idle away a few minutes waiting for train this is excellent value and highly recommended.