Book problems

[TKYMNK]

Hi! I am new here, as you can easily deduce, and I approach you with doubt and, why not say that, desperation. That said, I would like to take chance of my situation, not only to come here and cry on your shoulders, but to enjoy the website and your voices.
Let me tell you. A few days ago I was reading The Count of Monte Cristo by Dumas (excellent) and I saw some little orange-brown bugs. Yes, those dust bugs that get into books. I found a couple more in other books I had on my nightstand and I decided to make a radical decision: clean book by book. Obsessively, I have been removing them from the shelves, dusting, cleaning and spraying a special anti-mite spray that the drugstore told me was okay to use in places with books.
You can imagine that it has been a moment of sadness and tension: the appreciation I have for books is indescribable, so any stain has been observed with obsession... And fear. In some old books I found those very typical brown stains — and I no longer remember if they were there when they came to me or if they have been appearing. The striking, and disturbing, thing is that I have also found them in books... New ones. I imagine that it could be, 'simply', the poor quality of the paper, a specific defect... Or something else. Do any of you know how I could identify the problem? Does anyone know if these are 'normal' spots (and not 'contagious') or could it be... a fungus or something strange?
I leave you some pictures. Cause I amb not allowed to post images, I share a link in drive!).
Thanks!
(P.S.: I hope I'm not in the wrong section when posting the message here! ).

https:// drive.google .com/drive/folders/1DtPbSRC0TTUMtk3rs8WcBO7mWqwdju3K?usp=drive_link

1) Cien años de Soledad by GGM, edited by Mondadori (9ª edition, 2013). Stains appear on the first page (the courtesy page) and on some pages. This is the case that catches my attention the most, because it is a fairly new book.

2) Pedro Páramo y El llano en llamas byJuan Rulfo. Edited by booket (Planeta) in 2008. Since it's printed by Planeta —on who knows what quality of paper—, I don't know if it's normal for all these spots to appear.

3) Amalia by José Mármol, edited by Austral (5ª edition, 1978). Curiously, in this case only spots appear on the top of the book.

[Jacob Mamman]

A factor that can make a book hard to read is complex or technical vocabulary. This can often be the case with books about specialized topics, such as science or medicine. If you encounter a word you don't know, it can be difficult to continue reading without looking up the definition.

[Gee-Q Mdluli]

I've had books with those spots when I was younger, and in my case, I had spilled some drinks on them. The best thing to do is to separate them from your other books to prevent the mold from spreading.

Regarding book problems, one that I find far worse than anything else is something I've experienced more often than I care to admit: when I borrowed books from the library and later discovered missing pages

[Upphilan Paul]

One of the major book problem I have experienced was fainted word and I could get what was missing there.

[Lizzie Mustard]

Mildew affects books which have not been stored in dry conditions. It's a form of fungus. It can be killed (but not removed) by placing the books in the freezer for at least 24 hours. Make sure the pages are opened afterwards and allowed to airdry. Unfortunately once pages have been affected in this way, they are permanently marked.
If you are finding that your new books are also being affected then you should consider getting a dehumidifier for your home as the air is slightly damp.

[Christine Catarino]

@Lizzie Mustard Thank you as I just learned something new! Personally, I have not had any issues with my books, some of which I have had for over 20 years. But I recently bought some first editions while in Ireland, and I'm extremely concerned about anything happening to them!