An item in Pokémon Scarlet. It was written by Heath, and depicts Koraidon on its cover. Its counterpart is the Violet Book.
There exist multiple copies. Heath's original copy was passed down to his descendant, Briar. Another copy was given by Professor Sada to Arven, who gives it to the player, who in turn gives it to AI Sada. The player can later receive another copy from a time-displaced version of Sada.
