Special Rule - Grimoire
To write down a spell, you must first have cast it (and chance casting doesn't count)...
Hi Fenhorn, I'm curious about the part of your comment I've highlighted: is this a house rule or the books specifically say a character can't write down into a grimoire a spell previously cast with the "chance casting" option?
Edit: nevermind my question above - the text entry for Grimoires in the Player's handbook (p.120) is another change introduced in the second printing that wasn't included in the official list of changes published by Fria Ligan!
Indeed, a player's character can no longer have access to Rank 3 spells in the first quarter day of a campaign by chance-casting spells into a grimoire. Excellent!