A Book of knowledge was a possible reward from the random event gift. It gave you experience equivalent to your level in a skill times 15. Compared with a normal random event lamp, which only gave the experience equal to the level times 10, the book of knowledge provided 50% more experience.
If you tried to bank it, you would receive the message "A magical force prevents you from banking this item!".
Before the random event gift released, if a player still had a Book of knowledge in his or her inventory, it was very unlikely but not impossible for a player to receive the Surprise Exam! random. However, the player would only retain one Book of knowledge.
Before the aforementioned update, if no inventory space was available, the book was left on floor. But once it was picked up it was impossible to put it down again. However the "Book on floor" phenomenon has been discontinued, as the random event gift would provide space for the book.
The Book of knowledge was presented as the tome of experience, since a player had proved his or herself capable of solving the multiple questions presented by the dragon Mr. Mordaut.