Burning books (3)
I believe the answer is:
lit
This clue is a double definition.
'burning' is the first definition.
(I've seen this in another clue)
'books' is the second definition.
(abbreviation for literature)
(Other definitions for lit that I've seen before include "landed here" , "fine writing in condensed form" , "Set afire" , "was illuminating" , "Fired" .)