Book van, going back round Northern Ireland (6)
I believe the answer is:
daniel
'book' is the definition.
(book of the Bible)
'van going back round northern ireland' is the wordplay.
'van' becomes 'lead' (van can mean the front of something).
'going back' shows that the letters should be reversed in order.
'round' means one lot of letters goes inside another.
'northern ireland' becomes 'NI' (abbreviation).
'lead' backwards is 'dael'.
'dael' placed around 'ni' is 'DANIEL'.
(Other definitions for daniel that I've seen before include "-- Barenboim, -- Boone" , "Lions' den survivor" , "Hebrew prophet rescued from lion's den" , "Author of 11 16" , "Old prophet" .)