Intelligence requirements for books are largely meaningless

If your INT is lower than a book’s nominal INT requirement, then each reading session with the book takes 1 turn longer to complete for each point of difference. However, a single reading session typically takes tens or hundreds of turns to complete, so a single-digit turn penalty for failing the requirement is almost meaningless.

This effect is hard to notice in normal play, because INT has considerable effects on reading time and experience gained per reading regardless. However, the warning for missing the requirement suggests that time costs explode once you dip under it, which really isn’t the case.

Nice catch! From what I can tell the problem is that the penalty for having a low INT isn’t being multiplied by the time length of the book (meaning that the penalty for a 10 minute book or a 30 minute book would be the same, 6 seconds per INT short). I’ve just put up a pull request that adds that in, meaning if it gets accepted the new penalty should be a 10% increase in read times per INT missing (meaning a 10 minute book becomes an 11, a 30 becomes a 33, and so on for 1 INT missing).