Forces on standby may get books (8)
I believe the answer is:
reserves
I believe this clue is a double definition.
'forces on standby' is the first definition.
(as in army reserves)
'books' is the second definition.
(I know this)
'may get' acts as a link.
(Other definitions for reserves that I've seen before include "group of people for backup?" , "Books" , "Stockpiles" .)