City is a 1952 science fiction story collection by Clifford D. Simak that present a series of eight legends by the Dogs as they look back on a mythical creature called Man. The collection begins with an Editor's Preface that asks:

"What is Man?" ...

Or perhaps: "What is a city?"

Or: "What is a war?"

There is no positive answer to any of these questions.

As the stories unfold, they tell of a world where humans, having developed superior transportation fast enough that they no longer need to live anywhere near where they work, have moved away from the cities and into the countryside. Cities have become a thing of the past. The stories tend to focus around the Webster family, and their robot servant, Jenkins.

Each story tells of another breakdown of some sort of normal human life. The first is simply mankind abandoning the cities for the countryside, then becoming increasingly isolated untill they all suffer from agoraphobia. We see how one Webster son gives dogs a means of speech and better vision. We also see how the breakdown of civilization allows wandering mutant geniuses to grow up unrestrained by conventional mores. All of these breakdowns eventually lead to humans abandoning their human form to live as incredible natural beasts on Jupiter, essentially spelling a voluntary end to human evolution.

Simak is unique in that his vision of the apocalypse isn't one of destruction, but simply one of isolation. Humankind becomes so lonely that it eventually kills itself off in favor of starting over as a completely different species capable of experiencing the simply bliss that humankind has lost.

Earth is left to the dogs, robots, and surprisingly, ants. The few humans left on earth eventually revert to a primitive state, and much to Jenkins' dismay take up the age old tradition of killing once again. Eventually the dogs simply leave earth with the help of Jenkins to other worlds/realities.

The story was written in the post-WWII world, and reflects an attitude not uncommon at the time that humans weren't able to live at peace with their environment. There is an underlying theme throughout the book that there is simply a fundamental flaw in the way humans are built that we will never be able to overcome.