Investigation after error where books are kept (8)
I believe the answer is:
slipcase
'where books are kept' is the definition.
The definition suggests a singular noun which matches the answer.
'investigation after error' is the wordplay.
'investigation' becomes 'case'.
'after' says to put letters next to each other.
'error' becomes 'slip' (slip is a kind of error).
'case' after 'slip' is 'SLIPCASE'.
Can you help me to learn more?
(Other definitions for slipcase that I've seen before include "work cover" , "Book holder" , "one holding books?" .)