Why are the edges of expensive or cherished books often gilded? My guess is that it’s one more way of making a book into a fancy work of art. But apart from that, is it helpful to the paper? Does it help preserve the pages? Gold is certainly a great metal for resisting and preventing corrosion.
Sez here (in a 1915 book on bookbinding):
So while I kind of doubt that edge-gilding has any practical purpose in terms of physically preserving the book, it is definitely useful for making a book look like more of a luxury item than it is, as well as providing an elegant detail on books that really are luxury items.
Funny. Something I thought made it fancy is really to disguise cheap quality.
Several years ago when I worked in a used book store, I was told by a rare book dealer that gilding made books less attractive to vermin such as silverfish and book lice. I don’t know whether this is true or not, but I thought I’d pass it along.