Lawman from New York seizing books artist brought back (6)
I believe the answer is:
'lawman' is the definition.
(a notary is a legal official)
'new york seizing books artist brought back' is the wordplay.
'new york' becomes 'ny'.
'seizing' indicates putting letters inside.
'books' becomes 'OT' (abbreviation for Old Testament).
'artist' becomes 'RA' (Royal Academician, member of Royal Academy of Arts).
'brought back' is a reversal indicator.
'ra' backwards is 'ar'.
'ny' enclosing 'otar' is 'NOTARY'.
'from' acts as a link.
(Other definitions for notary that I've seen before include "Person authorised to witness signatures, etc" , "Public records official" , "Legal functionary" , "Official working on legal documents" , "Person legally authorised to witness signatures" .)