How to deal with Authors' books?

This is what I do with my Sim's books. I copy/paste them through this method in public libraries and some other Sims' homes, so everyone can read them. Because obviously, if my Sim is going to publish a "best-seller" book, the only logical thing is for every Sim to be able to access it.

As SheriSim said, you can copy your books with each sim, put them in a bookcase then make a room to upload to your build library. From there you can download in to each author's home and add books to it and update the one in your build library with the new one. You can place the bookcase from there into a library and add the books there. I made a library and wanted skill books in it years ago, and I had to put a bookcase into the library and the books I wanted on the lot while in build mode. I then went to live mode, had a sim go to the library and clean up the books. It worked then so hopefully still works now.  I love your idea! Really enjoy the writing career, especially now that we can write horror books with the Life & Death pack as well! You could do the same with putting books into a retail store.

My Rock Star's wife penned a biography about her husband and won a Starlight Accolade for Best Book. That was fun.

I make GREAT money selling my author sims books in a small business in retail shelves. He’s a spell caster, so I use the copypasto spell to make copies anytime she writes a best seller. I keep a copy for her and send it off to the publishers for daily royalties. 

I dont know how it works exactly but I had Gilderoy Lockhar make like 50 or a 100 copies of his book "Magical Me" xD and then I forgot all about it and recently playing as a different sim, I stumbled upon it in the Spa 🙃

I made a library for a community lot years ago and did something similar to what SheriSim​ recommended in that I added tons of books (skills, etc... I think all of the books from the packs I had at the time, etc.) and left them lying around on the floor and tables on the lot. I did that with a High School that I made, also, in the library I added on that lot. I found in both cases I could place the lot from the gallery or from my library into my save (with the books lying all over the floor, so it looks rather chaotic) at first and that sims would autonomously shelve the books, or sometimes I had one of my sims(s) go in live mode onto the community lot (after it was placed in the game save) and shelve the books to get it done with. Then after that point all of those books were available on that lot and found in any of its bookshelves. Of course, once they are shelved if you save it the lot to the library or gallery the books will be gone. If you want to see how they work, "Rockridge Academy of Arts" is the high school I mentioned and "Conservatory Library" is the library.

I never thought about experimenting with saving them into a room (to place on the lot to dump the books there in a similar manner, which is a great idea), and I very much look forward to hearing the details of how this works in regards to your copies of the books your sims write! I have done a touch of experimenting with books they write and bookshelves, but I don't remember how far I got.  If the book copy will successfully upload to your library I am assuming that will sever any ownership, which would hopefully solve that issue and maybe make it function like other books on a public lot? Of course, by any of the methods I mentioned I'm sure your sim would not get any of the profits, but as mentioned elsewhere, you should be able to publish  the original to make 'actual' profits. Anyway, I look forward to details!