Alternative Dimensions is the fourth book in a shared hard-science-fiction timeline, and the inside-view companion to Alternative Worlds. Where the earlier book told the outward life of Eleanor Anne Maxwell across three centuries (the bomb, the three bridges of longevity, the crossing into the substrate, and the long voyage outward from Earth), this one tells the same life from within, and carries it a fourth century further, all the way to the genie's world.
It is the story of the dreams that were not dreams. Across her whole enormous life, at the steady interval of about once in forty years, Eleanor dreamed of a vast blue figure rising over a heavy red world beneath a blue-white sun: a being who could casually conjure forests, cities, and whole turning worlds out of empty air. She first dreamed it as a sleepless child, and could make nothing of it for two hundred and fifty years. She learned, far too late to use the knowledge, that the dream was a true thing seen early, a flash forward down the long harmonics of the membrane that lies between the worlds, to the Jathuun of Alphecca: the genie-civilization whose heavy red world, under its blue-white sun, had been the true destination of her four-hundred-year journey all along.
For the Jathuun are the hinge of everything. In the four centuries this book spans, from a kitchen floor in 1961 to a heavy world under a blue sun in 2347, humanity climbs from a frightened planet that could barely manage its own weather into a Type II civilization, a mind very nearly the size of a star. And it is the genies, met first in dream and at last in the flesh, who hand it the final craft: the working of the membrane itself, the stepping between worlds by will alone. Eleanor's own road runs the same way, from the Earth she was born on, to a first new world forty-nine light-years away, on to Alphecca itself, where she lives the last sixty-nine years of this account as an apprentice to the civilization she had been dreaming since childhood.
And it does not end on the genie's world. In its final pages, at the very edge of the human survey in the year 2347, two further powers come into view: the Bright and the Infinity, intelligences of an order beyond even the genies, Type III where humanity has only just become Type II. What they are, and what they will mean for the century to come, is where this volume sets down its pen and the next takes it up.
Spanning four hundred years and two hundred and three worlds, Alternative Dimensions is at once a hard-SF chronicle of longevity, machine intelligence, and first contact, and the intimate interior story of one woman who refused to die before she understood her own dreams. It can be read on its own, but it is best read alongside Alternative Worlds, with which it shares a chronology, a narrator, and a final line.
