After a book has been around a while, there's more to it then what the publisher originally put on the shelf. For me, that's were the fun begins. You see, throughout the ages, people have customized books by adding messages, stampings, inserting book plates, flattening flowers, and leaving bookmarks and other goodies between the pages. I love books. And I especially love it when they've been around a while and they've been passed around and things have been added. [But only in an appropriate sense...not margin notes, highlighting, or other idiotic vandalism.]
This is one example of a worthwhile addendum. When the author or someone famous sends a book to someone else and makes a notation of the transaction, the book is sometimes referred to as a "presentation copy." In this case, the Rev. Cletus J. Welfrich of the Diocese of Raleigh gave a 1907 copy of Trails and Triumphs of the Catholic Church to the Archbishop of Chicago, Patrick A. Freehan. Presentation inscriptions are relatively uncommon. However, they are similar to gift inscriptions, which are frequently seen. You'll often find books that are simply signed by the author, which, in some cases can add tremendous value.
But I'm also interested in what previous owners leave between the pages. This type of ephemera is know as fly-aways in the book trade. I've seen every manner of fly-aways--from cash register receipts to bookmarks to postcards, photographs, and even a bubble gum wrapper.
As a book ages and travels around a bit it gains character, just like some people do.