In the year 2034, Theo Quderian, a French physicist, made an amusing but impractical discovery: the means to use a one-way, fixed-focus time warp that opened into a place in the Rhone River valley during the idyllic Pliocene Epoch, six million years ago. But, as time went on, a certain usefulness developed. The misfits and mavericks of the future-many of them brilliant people-began to seek this exit door to a mysterious past. In 2110, a particularly...

In the final novel of the award-winning sci-fi saga, both humans and aliens face destruction as a new time-portal opens a path back to the twenty-second century. Human time-travelers from the sophisticated Galactic Milieu of the twenty-second century came to the Pliocene Epoch seeking a Garden of Eden. What they found was slavery under the knightly Tanu race, who had been exiled to Earth from a far galaxy. Freed by the usurper Aiken Drum, the humans...