Model chapter extracted from great book (7)
I believe the answer is:
epitome
'model chapter' is the definition.
'epitome' can be an answer for 'model' (epitome can mean a model or example). I am not sure about the 'chapter' bit.
'extracted from great book' is the wordplay.
'extracted from' becomes 'epi' (I am not sure about this - if you are sure you should believe this answer much more).
'great book' becomes 'tome' (a tome is a large book).
'epi'+'tome'='EPITOME'
(Other definitions for epitome that I've seen before include "Perfect example of a quality" , "Summary of a written work" , "Model" , "Ideal example" , "Paradigm" .)