"I, Robot" author Isaac (6)
I believe the answer is:
asimov
'i robot author isaac' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for asimov that I've seen before include "Isaac --, sci-fi author" , "Author of "Three Laws of Robotics"" , "Isaac -, US sci-fi writer" , "novelist" , "Isaac - - , SF writer" .)