Definition of book up:
(v) :
(transitive) To reserve or book all of something, for example by purchasing all the tickets.
(v) :
(intransitive) To have all of its tickets or reservations purchased.
(v) :
(transitive, slang) To study or learn (something).
(v) :
(chess, slang) To study opening lines in great detail in order to gain an advantage.