Decide books should be removed from remains of building (4)
I believe the answer is:
rule
'decide' is the definition.
(I know that rule is a more specific form of decide)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for rule that I've seen before include "Control, government" , "Exercise authority over" , "Control; printed line" , "Standard" , "Government; regulation" .)