I am reading through Good Omens and finding quite a few instances of words written with f's in place of long s'es.

Is it a conscious pun on modern readers mistaking ſ for f, or a mistake on the authors/typesetters part? Futhermore, the use is inconsistent, and same passages often contain words written with both the long and the terminal s in the middle of the word with no discernible pattern.

I'm 99% certain that's a joke about old English spelling.

Notice that the characters who speak that way are all from centuries past, like Agnes.

Thank you for posting this information!)