Short book Harry lent to Eve (9)
I believe the answer is:
novelette
'short book' is the definition.
(I've seen this before)
'harry lent to eve' is the wordplay.
'harry' indicates an anagram (harry can mean to attack or spoil).
'lent'+'to'+'eve'='lenttoeve'
'lenttoeve' anagrammed gives 'NOVELETTE'.
(Other definitions for novelette that I've seen before include "Short work of fiction" , "romance?" , "Short book of fiction" , "Short and light tale" , "Short story" .)