Maybe people who like Tolkien books back in nick (7)
I believe the answer is:
snaffle
'nick' is the definition.
(both can mean to steal or take)
'maybe people who like tolkien books back' is the wordplay.
'maybe people who like tolkien books' becomes 'elf fans' (JRR Tolkien wrote about elves).
'back' says the letters should be written backwards.
'elffans' in reverse letter order is 'SNAFFLE'.
'in' is the link.
(Other definitions for snaffle that I've seen before include "Get hold of" , "A bit; steal (colloq.)" , "A bit; filch" , "Horse's bit" , "Appropriate" .)