Did he deliver as US novelist? (6)
I believe the answer is:
mailer
'novelist?' is the definition.
(I've seen this before)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for mailer that I've seen before include "Norman --, US author" , "writer from America" , "American author of The Naked and the Dead, d. 2007" , "novelist" , "person at the post?" .)