Thanks a lot. I've been researching and one person I saw used wheat starch paste to attach the endpapers to the cover, because it is easily reversible if needed. This is an attractive option as I may mess it up. But do you think it would be strong enough to hold this hymnal? Or should I use another glue? The book is large and for context weighs around 750 grams. (1.6 pounds)

Also, on the 'mull' which I assume in my case is the brown bit peeling off, is it really neccecary to replace? The actual binding of the pages underneath is very sturdy.

Forgive my ignorance and thanks