[Foundation's Edge] takes place several hundred years after the close of Second Foundation…. The First Foundation on Terminus and the Second Foundation on Trantor suspect each other of manipulating the Seldon Plan for the restoration of Galactic to its own advantage. Each sends out agents, and the adventures of these agents (including their search for Earth) make up the bulk of the novel. This is Asimov's longest novel and is distinctly uneven; the opening is positively sluggish and many settings and characters fail to come to life. On the other hand, a large part of the book is essentially a cross between sf and the detective story, where Asimov's skill is as great as ever. Asimov also appears to be planning future Foundation novels as part of a grand scheme to tie together into one future history his robot novels, the Foundation saga, and the Galactic Empire novels...