The Use text is a little odd in that it notes the "tome is consumed when read." To me that means that the book is only a one use thing, which is a departure from current BoA items. And why have a level 68 requirement on this and not the normal Cold Weather Flying training? If you're 68 you're likely to be able to get to Dalaran anyways these days.
But wait Did you see it? You might have missed it.
It shows level 68 being the required level, not level 77.