Rigglesford's book is mainly concerned with shooting schedules. eg. "Studio work on 'Breakdown' was finished by Lorrimer following two days of work on 11-12 February."
There is an episode guide which isn't always correct. For instance the entry for Horizon states that "Blake teleports down with all his crew except for Avon." Well they may have all gone down, but they certainly didn't go together. The entry for Deliverance doesn't even mention Meegat and her rocket. Duel gives totally the wrong motive to Sinofer and Giroc.
Other areas are also inaccurate. I can't speak for all the cast, but I'm darn certain that the photo of Gareth Thomas labelled as being from a restoration commedy is in fact from 'The Life of Thackery'.
There are a lot of new photographs. The reason many of them haven't been seen before is because they aren't terribly good. There are some good ones, but not that many considering that there is a picture on every page.
The layout has a frequent habit of superimposing text on pictures which makes it harder to read.
If you want to know who directed what and when and where filming etc. took place, and can't get hold of a copy of the Marvel Summer Special (which had the same information at a much lower price but is no longer available) then I guess it is worth getting, but don't bother otherwise.