Edits Socialist book (7)
I believe the answer is:
redacts
'edits' is the definition.
('redact' can be a synonym of 'edit')
'socialist book' is the wordplay.
'socialist' becomes 'red' (red can informally mean a socialist).
'book' becomes 'acts' (book of the Bible).
'red'+'acts'='REDACTS'
(Other definitions for redacts that I've seen before include "Changes the text" , "Censors part of a text before presentation" , "Edits or censors before publication" .)