The problem with the Ribble from a book writing point of view is it's clubed up and very few dayticket lengths. Many of the controlling Clubs have a no publicity policy.
For someone to write such a book, they would, without permission from the clubs, put their membership at risk.
If however, someone did write a book about the river who no longer fishes the river and is no longer in the controlling clubs, the info would be old and out of date.