In previous posts, in case you didn't see them, I list that one reason to give extra care to a paperback book is if it is sentimental. Many paperbacks aren't and can easily be replaced cheaply from thrift stores and used bookstores. Another reason to restore and repair what you have is because you have notes written in the margins (I love reading other people's marginalia :-) ). A third reason is if you have an author-signed paperback or two in your collection, and you want to pass it down to family members to enjoy for years. These are three main reasons to opt for archivally safe products for restoring and conserving favorites in your collection to pass down to your children and grandchildren.
You could argue that the signed book shouldn't be touched at all. True to a point, but books are for reading and enjoying, so I will give it my best archival repair with a minimum of interference in order to preserve it for my family.
The first step I demonstrate will work well on page mends, as well.
The mending tissue can be purchased here. You can probably hear the frustration in my voice at the difficulty of figuring out how to work with this tissue for the first time. This is buyer beware number one, but really, the problem was quickly resolved, and all is well. Another buyer beware is that the description in the title says this box contains 1/2" x 600" but when I received it, it was only 50" long. It is still cheaper to buy it through amazon than through lineco.com.
The product I use for adhering the half-torn-off cover to the text, gummed linen book repair tape, is found here. In the video, I said it was about five dollars. I was off by a buck, as it is $3.94 with free shipping through amazon prime.
I am very pleased with how both work and with how the job turned out afterwards!
Have fun and ciao for now!