Due to their intended use and restrictions on the then theater owners, pressbooks are often extremely hard to find in any condition as they were sent to movie theaters to be used to cut newspaper ads out of, etc. it is normal that there are some cut pages and the books are most often found folded as they were sent through the mail (often bundled with the film and posters).
This fold may result in small cover separation at very center of spine from opening. Condition statements are based on this normally found and as sent condition (therefore, "mint" examples are rarely noted here and we would rather be conservative.). Cuts will always be noted.
In many cases, the pressbook from movies are very much harder to find than the posters themselves which were often stolen for wall display by owners and employees or, more often, thrown away.
Because of their rarity, press books represent one of the better Movie collectible investments. The same was once true for original Posters and we all know how valuable those are today!