alt Hacker NewsYou may recall that the DMCA was originally written to protect music and movies. It does in fact apply to creative works. If you have ever purchased an MP3, eBook, or streaming movie, you will also be aware that you purchased a license to the underlying IP. This is also true of physical media, but the license agreement you have to accept when obtaining a digital work makes this explicit.
I agree that you can't patent a book, but I would point out that you can patent an idea, which may only appear in a book or journal article.
You do patent ideas, but the actual words written in a book describing that idea would only be protected by copyright at best. FWIW, the exact words describing the idea being patented are technically public domain; that's the whole point. You're free to go look up that patent, print it out, make whatever copies of it you want. Take any of the drawings in patents, put them on t-shirts, and sell them. No problem. Implementing the ideas those words represent is a different story.
For example, a patent describing a chemical process. The actual idea of how to do it is public domain, go look up the patent. Print it out. Do whatever with those words. Its fine. Building a plant to go do that chemical process to make that same output chemical in that same way, that's IP infringement. Its not the words, its the idea.