Perfect example in English, very good book (7)
I believe the answer is:
epitome
'perfect example' is the definition.
(the epitome of a thing is a perfect example of it)
'english very good book' is the wordplay.
'english' becomes 'e' (abbreviation).
'very good' becomes 'pi' (old-fashioned term for 'pious').
'book' becomes 'tome' (a tome is a book).
'e'+'pi'+'tome'='EPITOME'
'in' is the link.
(Other definitions for epitome that I've seen before include "Abstract" , "ie Tempo (anag.)" , "Summary; embodiment" , "Archetype, typical example" , "Perfect example of a quality" .)