From the introduction: A chilling selection of new rules for players and DMs to enhance your Icewind Dale: Rime of the Frostmaiden campaign. Knuckleheads & Other Such Curiosities - A Traveler's Guide to Icewind Dale is intended to be a companion to Icewind Dale: Rime of the Frostmaiden that you can use to flesh out that campaign or make your own games, all while being useful for your DDAL - D&D Adventurers League characters or your home game.