Foundation's Edge is Isaac Asimov's 4th installment in his Foundation series. Book 4 opens almost 500 years through the Seldon plan. A Councilman of the 1st Foundation as well as an up and coming youthful Speaker of the 2nd Foundation become worried that everything is going too well and suspect another party is intervening. Each is also on the outs with their own leadership for their nearly blasphemous ramblings. The Councilman is maneuvered into exile, but secretly in search of the suspected 2nd Foundation with an historian in search of the mythical humanity's origin planet, Earth. The 2nd Foundation Speaker believes a more powerful version of the 2nd Foundation may exist. What they encounter is a world that even the Mule was reluctant to tangle with. The fate of the universe is to be decided among three distinct and non-overlapping options.
Asimov continues the technological advances with the 1st Foundation gaining control of gravitics and superfast space travel such that it remains an open question as to whom is more powerful, the 1st Foundation's technology versus the 2nd Foundation evolving mind control. Each of these alternatives presents an interesting vision for the galaxy's future. At the same time, he also introduces the concept of Gaia that is a hybrid of a hive mind with community level symbiosis that extends not only to all living matter, but to inanimate material as well, basically the whole planet. While a choice is made, it represents more the safe, hedged bet, rather than a clear right choice.