So, what should those stories be about? That's what I asked myself, and after giving it some thought, these were my answers, or rather, the questions I determined Asimov had left unasnwered:
- At the end of Foundation ad Earth, we were left with several unanswered questions. How would Daneel merge his brain with Fallom's? What happened to the virus the Alphans had given to the protagonists? What would happen to the Solarians? Did Daneel know what happened to Melpomenia and Aurora? Were our protagonists going to visit those other 47 Spacer worlds too, and what would they find there? What alien threats might Daneel's Galaxia have to face?
- At the end of Robots and Empire, Undersecretary Quintana is still waiting outside for Daneel. How is he going to explain those two unconscious Auroran prisoners and the deactivated Giskard? How would he explain the presnece of those Aurorans there without inciting an interstellar conflict at a time Settlers and Spacers are trying to lay bridges and work together? Would he be able to persuade her to trust him and keep it secret? Would he need to use his newly acquired mental powers on her for that? Would he trust in his ability to use them without causing any harm? After Amadiro and Mandamus had their plans wiped off their memories, what would they still remember about having traveled to Earth, and what other effects may the wipe have had on them? And since Foundation and Earth had established D.G. had taken Gladia to Melpomenia too, when would they head over there, and what for?
- The previous ones were the questions I had mainly thought of 25 years ago, but now I thought of some additional ones. What happened between Mother Earth and The Caves of Steel to change what the Pacific Project had expected to achieve after 100 years? Why weren't robots widely adopted on Earth yet, even after 1000 years? Why did the Spacers establish Spacetown, when they had expressed their intention to leave Earth alone forever? How did the Cities grow and why were ground vehicles mostly abandoned (except for use by the authorities, apparently) in favor of conveyor belts?