Things to keep in mind:
The secret of the series.
The particular form I’m talking about is probably clearest in the Foundation tales, though you can trace it out in almost all the others. Put simply, the first story poses a problem and finally offers some solution. But in the next story, what was the solution of the first story is now the problem. In general, the solution for story N becomes the problem for story N+1. This allows the writer to go back and critique his or her own ideas as they develop over time. Often, of course, the progression isn’t all that linear. Sometimes a whole new problem will assert itself in the writer’s concern—another kind of critique of past concerns. Sometimes you’ll rethink things in stories more than one back. But the basic factor is the idea of a continuous, open ended, self-critical dialogue with yourself.
—posted 1757 days ago