Imbuements: (Empty Slot).
You don't need to carry your spellbook with you all the time, it isn't necessary to have a spellbook to cast a spell. It does, however, tell you which spells you have, as well as the mana and the words needed to cast each spell. The spell words can also be found at the official web site, at the ingame Spell List or on the Spells page. It looks the same as an Almanac of Magic, Nature Magic Spellbook and Spellbook of Dragha. It has been made somewhat redundant by the Flash Client's ability to list a character's known spells.
See also: Spellbook (Alternative)