The tome of xp 2nd ed is given as a reward for completing the Legacy of Seergazequest. It gives the player 2,500 experience points in any skill that's at least level 35, up to 3 times in total.
Reading it opens a window for the player to select the skill they wish to advance in. This message also appears in the chat box - "Choose the stat you wish to be advanced!" After confirming your choice, this message will appear in the chat box - "You read a fascinating chapter and earn experience!"