Lecturer working with fellow author (6)
I believe the answer is:
london
'author' is the definition.
(Jack London)
'lecturer working with fellow' is the wordplay.
'lecturer' becomes 'l'.
'working' becomes 'on'.
'with' says to put letters next to each other.
'fellow' becomes 'don' (I've seen this before).
'l'+'on'+'don'='LONDON'
(Other definitions for london that I've seen before include "UK's capital" , "City of the Cockneys" , "City for the odd non-old" , "City of Piccadilly" , "England's capital city" .)