Muse books live return (5)
I believe the answer is:
erato
'muse' is the definition.
(I know that Erato is a muse)
'books live return' is the wordplay.
'books' becomes 'OT' (abbreviation for Old Testament).
'live' becomes 'are' ('they live' means 'they are').
'return' shows that the letters should be reversed in order.
'ot'+'are'='otare'
'otare' written backwards gives 'ERATO'.
(Other definitions for erato that I've seen before include "Clio's sister" , "One of nine" , "Source of artistic inspiration" , "Poet's muse" , "Greek muse - orate (anag)" .)