book script command is used to open/close the player book and/or change the page.
book [-aem] open
book [-aem] close
book [-aem] change
-a: Switch to the map page
-e: Switch to the spell book page
-m: Switch to the quest log page
This command does not check if a book page is accessible to the player. This means it lets you switch to the spell book before acquiring any runes. Does it break anything? No. Is this useful? No. But you can do it.