The publisher/author has to include page numbers in the book before this option can display. I think page numbers are in a separate file. Any old Amazon books that have not been updated since the introduction of page numbers to the system, will of course not have them. Those Manchester volumes are really old. I read them in pBooks 30 years ago I think. Well the first two anyway.

If a book on Amazon.com has page numbers included, there is a notice in the book description saying it has real page numbers included.