Smart, perhaps, consuming volume after volume (5)
I believe the answer is:
savvy
'smart' is the definition.
(I've seen this before)
'perhaps consuming volume after volume' is the wordplay.
'perhaps' becomes 'say' (both can mean 'for example').
'consuming' means one lot of letters goes inside another.
'volume' becomes 'v' (abbreviation for volume in book titles).
'after' is a charade indicator (letters next to each other).
'volume' becomes 'v' (abbreviation for volume in book titles).
'v'+'v'='vv'
'say' enclosing 'vv' is 'SAVVY'.
(Other definitions for savvy that I've seen before include "Possessing the required knowledge" , "Shrewd, knowledgeable" , "Astute" , "Knowing" , "smart" .)