Mastermind in Greene novel (8)
I believe the answer is:
engineer
'mastermind' is the definition.
('engineer' can be a synonym of 'mastermind')
'in greene novel' is the wordplay.
'novel' is an anagram indicator.
'in'+'greene'='ingreene'
'ingreene' with letters rearranged gives 'ENGINEER'.
(Other definitions for engineer that I've seen before include "One who designs, makes or runs motors" , "Skilfully arrange" , "Applied technologist" , "Practical technologist" , "Person who uses scientific knowledge to solve practical problems" .)