Brigand in book, with it (6)
I believe the answer is:
bandit
'brigand' is the definition.
('bandit' can be a synonym of 'brigand')
'book with it' is the wordplay.
'book' becomes 'b'.
'with' becomes 'and' (I've seen this before).
'b'+'and'+'it'='BANDIT'
'in' is the link.
(Other definitions for bandit that I've seen before include "Armed outlaw" , "Armed brigand" , "Outlawed robber" , "(One-armed?) outlaw" , "Desperado" .)