Possible Clues:

• SF writer announced when I'm leaving
• Russian-American sci-fi great
• Mavis sadly concealing love for sci-fi writer
• Isaac who wrote himself into 'Murder at the ABA'
• Russian-born American science fiction writer Isaac ___ , d. 1992
• Isaac --, sci-fi author
• 'Foundation' trilogy writer
• Writer is a revolutionary wanting endless progress
• Robotic, like Isaac?
• He wrote about robots almost synchronised with my gestures?