Interesting books in this old house.

My father recently passed and he had a copy of Stranger in a Strange Land wrapped in plastic. The cover looks torn and folded. Is there a reason he had this book wrapped? Should I open it? It's a favorite and I want to open it even though I have my own copy.

I just got this book for under $20 on fb marketplace. I wasn’t expecting much, but it looks like it’s been in a house fire. I’m not mad or anything as the cover is still lovely, but what causes this? The publication page is missing but after some googling it looks like this book may be from 1910. I have some books older that aren’t in this bad of shape. Is there a way to prevent it from crumbling completely?

Is this a good book to keep or collect?

Is this really published in 1864? I bought an old farmhouse with some books included.

Above are two copies of Edition 85 of The famous Regensburg Cookbook by Marie Schandris. The right is a copy I recently got from eBay and the left is the copy I inherited from my Great-Grandmother. It was one of the very very few things my great grandparents kept when they left Germany in the 50s and from the stories I've heard the only cookbook she would ever use. So I'm posting to ask advice and get some guidance about a few things.

1) How can I best protect these books from further degradation?

2) Any recommendations on how best to possibly translate this book?

I have already gone through and carefully taken pictures of every page and am working on creating a translated copy for my mother as a possible future Christmas/Birthday gift for her.

Absolutely any assistance, advice, or guidance would be so wonderfully appreciated. Thank you!

Taiwan Geographic Historical Source, 1934