Thank you for enjoying the game.
For the book issue you found, which version and platform are you playing?
Viewing post in Rewind: A Looping History comments
That issue was fixed in version 2.9. For people still playing the free versions, you can find a workaround for this issue (sorta) by reading the "Known Bugs" section in the Version 2.8 Changelogs up above. I hope this helps!
Known Issues:
- Skill books may trigger an error message after earning a new skill. Rolling back and the error screen should correct the problem.